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  • 1.
    Alfredson, Jens
    et al.
    SAAB, Linköping, Sweden.
    Johansson, Björn
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, Faculty of Arts and Sciences.
    Gonzaga Trabasso, Luis
    Aeronautics Institute of Technology, Brazil.
    Schminder, Jörg
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Granlund, Rego
    Research Institutes of Sweden SICS East, Linköping, Sweden.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    DESIGN OF A DISTRIBUTED HUMAN FACTORS LABORATORY FOR FUTURE AIRSYSTEMS2018In: ICAS congress proceeding, International Council of the Aeronautical Sciences , 2018, article id ICAS2018_0305Conference paper (Other academic)
    Abstract [en]

    This paper presents a rationale for structuring a distributed human factors laboratory for future air systems. The distributed herein refers to two aspects: content and geographic. As for content, the laboratory is structured in two levels, namely, individual, and team. As for geographic, the laboratory infrastructure is distributed in three physically separate facilities, namely, Department of Computer and Information Science (IDA) and Department of Management and Engineering (IEI) from Linköping University – Sweden and the Competence Center in Manufacturing from the Aeronautics Institute of Technology (ITA) – Brazil.

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    fulltext
  • 2.
    Bradley, Andreas
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Bird-Like Wing Conguration for Pitch Control of a Tailless Aircraft2012Conference paper (Other academic)
    Abstract [en]

    A numerical study of a small bird-like aircraft has been performed. The aim of the study was to investigate how a swing wing (actualized through a constant span morphing wing) can be used for pitch control of a tailless aircraft. The results show that a swing wing can be successfully used, and that the aircraft can be maintained in a trimmed state by only small adjustments of part of the wing. A comparison was also made with a Vortex lattice method, but these results significantly deviated from those obtained with CFD. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc.

  • 3.
    Dyverfeldt, Petter
    et al.
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, The Institute of Technology. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics . Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, The Institute of Technology.
    Sigfridsson, Andreas
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, The Institute of Technology. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics . Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, The Institute of Technology.
    Ebbers, Tinno
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, The Institute of Technology. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    MRI Turbulence Quantification2009In: Proc. Intl. Soc. Mag. Reson. Med., 2009, p. 1858-Conference paper (Refereed)
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    MRI Turbulence Quantification
  • 4.
    Dyverfeldt, Petter
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Sigfridsson, Andreas
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Ebbers, Tino
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    On MRI turbulence quantification2009In: Magnetic Resonance Imaging, ISSN 0730-725X, E-ISSN 1873-5894, Vol. 27, no 7, p. 913-922Article in journal (Refereed)
    Abstract [en]

    Turbulent flow, characterized by velocity fluctuations, accompanies many forms of cardiovascular disease and may contribute to their progression and hemodynamic consequences. Several studies have investigated the effects of turbulence on the magnetic resonance imaging (MRI) signal. Quantitative MRI turbulence measurements have recently been shown to have great potential for application both in human cardiovascular flow and in engineering flow. In this article, potential pitfalls and sources of error in MRI turbulence measurements are theoretically and numerically investigated. Data acquisition strategies suitable for turbulence quantification are outlined. The results show that the sensitivity of MRI turbulence measurements to intravoxel mean velocity variations is negligible, but that noise may degrade the estimates if the turbulence encoding parameter is set improperly. Different approaches for utilizing a given amount of scan time were shown to influence the dynamic range and the uncertainty in the turbulence estimates due to noise. The findings reported in this work may be valuable for both in vitro and in vivo studies employing MRI methods for turbulence quantification.

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    FULLTEXT01
  • 5.
    Ekman, Petter
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Virdung, Torbjorn
    ANSYS, Sweden.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Aerodynamic Drag Reduction of a Light Truck - from Conceptual Design to Full Scale Road Tests2016In: SAE 2016 World Congress and Exhibition, SAE International , 2016Conference paper (Refereed)
    Abstract [en]

    Considerable amounts of the everyday goods transports are done using light trucks. In the last ten years (2005-2015), the number of light trucks has increased by 33 % in Sweden. The majority of these light trucks are fitted with a swap body and encounter the same problem as many other truck configurations, namely that several different manufacturers contribute to the final shape of the vehicle. Due to this, the aerodynamics of the final vehicle is often not fully considered. Hence there appears to be room for improving the aerodynamic performance. In this study the flow around a swap body fitted to a light truck has been investigated using Computational Fluid Dynamics. The focus has been on improving the shape of the swap body in order to reduce both the aerodynamic drag and fuel consumption, while still keeping it usable for daily operations. Reynolds-Averaged Navier-Stokes simulations were used for concept evaluation while more advanced Detached Eddy Simulations were performed on the best concept in order to investigate details of the flow. Various concepts were evaluated from which it could be seen that a more streamlined top of the swap body together with a lowered top trailing edge had a significant positive effect on the aerodynamic drag. A full scale light truck was equipped with a swap body with with these modifications for road tests. During a test period, a mean fuel consumption reduction of 12 % was measured, thus indicating a significantly reduced aerodynamic drag.

  • 6.
    Ekman, Petter
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Virdung, Torbjorn
    ANSYS Sweden, Sweden.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Aerodynamics of an Unloaded Timber Truck - A CFD Investigation2016In: SAE International Journal of Commercial Vehicles, ISSN 1946-391X, E-ISSN 1946-3928, Vol. 9, no 2, p. 217-223Article in journal (Refereed)
    Abstract [en]

    Reducing energy consumption and emissions are ongoing challenges for the transport sector. The increased number of goods transports emphasize these challenges even more, as greenhouse gas emissions from these vehicles increased by 20 % between 1990 and 2013, in Sweden. One special case of goods transports is the transport of timber. Today in Sweden, around 2000 timber trucks transport around six billion ton kilometers every year. For every ton kilometer these vehicles use around 0.025 liter diesel, and there should exist large possibilities to reduce the fuel consumption and the emissions for these vehicles. Timber trucks spend most of their operation time travelling in speeds of around 80 km/h. At this speed aerodynamic drag contributes to around 30 % of the total vehicle resistance, which makes the aerodynamic drag a significant part of the energy consumption. One of the big challenges with timber trucks is that they travel unloaded half of the time. This put higher demands on possible drag reduction modifications, as they need to function and be practical for both when the timber truck is loaded and unloaded. In this study an unloaded timber truck has been investigated by use of computational fluid dynamics. The recently released Stress Blended Eddy Simulation model has been used for simulating the flow over a timber truck at a Reynolds number of 1.1 million, based on the square root of its frontal area. From the results it could be seen that 52.8 % of the drag is generated by the cab. By investigating a drag reduction device that covered the gap between the bulkhead and the first stake pair, a drag reduction up to 6.7 % was possible, which shows potential for simple modifications that not influence the daily usage.

  • 7.
    Ekman, Petter
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Virdung, Torbjörn
    ANSYS, Sweden.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Aerodynamic Drag Reduction - from Conceptual Design on a Simplified Generic Model to Full-Scale Road Tests2015In: SAE 2015 World Congress & Exhibition, SAE International , 2015Conference paper (Refereed)
    Abstract [en]

    Road transportation by trucks is the major part of the goods transportations system in the European Union (EU), and there is a need for increased fuel efficiency. While truck manufacturers already spend significant resources in order to reduce the emissions from their vehicles, most truck manufacturers do not control the shape of the trailer and/or swap bodies. These devices are usually manufactured by different companies that cannot consider the overall aerodynamics around the complete vehicle.By use of Computational Fluid Dynamics (CFD) and previous wind tunnel experiments, the flow around a simplified generic tractor-trailer model has been investigated. With better understanding of the flow features around the tractor with attached trailer or swap bodies, an improved design of the trailer and swap body can be achieved, which is the aim for the project. Special emphasis is put on achieving simple, easy to install or implement drag-reducing geometrical modifications to the trailer or swap bodies that can be mounted on existing trucks.Reynolds-Averaged Navier-Stokes (RANS) simulations were used for the conceptual development phase where trends in drag reduction due to the modified geometries were studied using a parameter study, while more advanced scale resolving simulations (SRS) were used in order to investigate the details of the flow fields.The investigation indicates that aerodynamic drag reduction is possible with quite simple geometrical modifications. Some of the results have also been verified through road tests of vehicles in commercial use, which has shown reduced fuel consumption of up to 5%.

  • 8.
    Gårdhagen, Roland
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Blodflöden i patientspecifika kärlmodeller - Simulering och koppling till sjukdomar2007In: Svenska Mekanikdagar,2007, 2007Conference paper (Other academic)
    Abstract [sv]

        

  • 9. Order onlineBuy this publication >>
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Turbulent Flow in Constricted Blood Vessels: Quantification of Wall Shear Stress Using Large Eddy Simulation2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The genesis of atherosclerosis has previously been shown to be affected by the frictional load from the blood on the vessel wall, called the wall shear stress (WSS). Assessment of WSS can therefore provide important information for diagnoses, intervention planning, and follow‐up. Calculation of WSS requires high‐resolved velocity data from the vessel, which in turn can be obtained using computational fluid dynamics (CFD). In this work large eddy simulation LES was successfully used to simulate transitional flow in idealized as well as subject specific vessel models. It was shown that a scale resolving technique is to prefer for this application, since much valuable information otherwise is lost. Besides, Reynolds‐Averaged Navier‐Stokes (RANS) models have generally failed to predict this type of flow.

    Non‐pulsating flows of Reynolds numbers up to 2 000 in a circular constricted pipe showed that turbulence is likely to occur in the post‐stenotic region, which resulted in a complex WSS pattern characterized by large spatial as well temporal fluctuations in all directions along the wall. Time averaged streamwise WSS was relatively high, while time averaged circumferential WSS was low, meaning that endothelial cells in that region would be exposed to oscillations in a stretched state in the streamwise direction and in a relaxed state in the circumferential direction.

    Since every vessel is unique, so is also its WSS pattern. Hence the CFD simulations must be done in subject specific vessel models. Such can be created from anatomical information acquired with magnetic resonance imaging (MRI). MRI can also be used to obtain velocity boundary conditions for the simulation. This technique was used to investigate pulsating flow in a subject specific normal human aorta. It was shown that even the flow in healthy vessels can be very disturbed and turbulence like, and even for this case large WSS variations were seen. It was also shown that regions around branches from the aorta, known to be susceptible for atherosclerosis, were characterized by high time averaged WSS and high oscillatory shear index.

    Finally, the predictive capability of CFD was investigated. An idealized model of a human aorta with a coarctation and post‐stenotic dilatation was studied before and after a possible repair of the constriction. The results suggested that small remaining abnormalities in the geometry may deteriorate the chances for a successful treatment. Also, high values of shear rate and Reynolds stresses were found in the dilatation after the constriction, which previous works have shown means increased risk for thrombus formation and hemolysis.

    List of papers
    1. Feasibility of Patient Specific Aortic Blood Flow CFD Simulation
    Open this publication in new window or tab >>Feasibility of Patient Specific Aortic Blood Flow CFD Simulation
    Show others...
    2006 (English)In: Medical Image Computing and Computer-Assisted Intervention – MICCAI 2006: 9th International Conference, Copenhagen, Denmark, October 1-6, 2006. Proceedings, Part I / [ed] Rasmus Larsen, Mads Nielsen and Jon Sporring, Springer Berlin/Heidelberg, 2006, 1, Vol. 4190, p. 257-263Conference paper, Published paper (Refereed)
    Abstract [en]

    Patient specific modelling of the blood flow through the human aorta is performed using computational fluid dynamics (CFD) and magnetic resonance imaging (MRI). Velocity patterns are compared between computer simulations and measurements. The workflow includes several steps: MRI measurement to obtain both geometry and velocity, an automatic levelset segmentation followed by meshing of the geometrical model and CFD setup to perform the simulations follwed by the actual simulations. The computational results agree well with the measured data.

    Place, publisher, year, edition, pages
    Springer Berlin/Heidelberg, 2006 Edition: 1
    Series
    Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349 ; 4190
    National Category
    Medical Image Processing
    Identifiers
    urn:nbn:se:liu:diva-36902 (URN)10.1007/11866565_32 (DOI)000241556300032 ()32988 (Local ID)3-5404-4707-5 (ISBN)978-3-540-44727-6 (ISBN)978-3-540-44707-8 (ISBN)32988 (Archive number)32988 (OAI)
    Conference
    The 9th MICCAI Conference, Copenhagen, Denmark, 1-6 October 2006
    Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2018-02-20Bibliographically approved
    2. Large Eddy Simulation of Stenotic Flow for Wall Shear Stress Estimation - Validation and Application
    Open this publication in new window or tab >>Large Eddy Simulation of Stenotic Flow for Wall Shear Stress Estimation - Validation and Application
    2011 (English)In: WSEAS Transactions on Biology and Biomedicine, ISSN 1109-9518, Vol. 8, no 3, p. 86-101Article in journal (Refereed) Published
    Abstract [en]

    Turbulent flow in the cardiovascular system may increase the risk for severe arterial disease. This workaddresses the feasibility of Large Eddy Simulation (LES) using a general purpose code as a tool for assessmentof cardiovascular flow and investigates Wall Shear Stress (WSS) in steady as well as pulsating turbulent pipeflow. Poiseuille flow was specified at the inlet, and with a suitable ammount of perturbations at the inlet it waspossible to predict experimental data. The extent of the recirculation zone was affected by the inlet disturbances,and magnitude as well as direction of the WSS vector varied significantly at the reattachment point. For thepulsating flow, WSS shows a complex pattern with different spatial and temporal variation along the pipe. Thewall shear stress gradient was calculated on the entire post-stenotic surface and each component in the gradientwas investigated. The off-diagonal components in the gradient are usually assumed to be small, but here they werefound to be on the same order of magnitude as the diagonal terms. This work demonstrates the need for a scaleresolving simulation technique to accurately model cardiovascular flows.

    Keywords
    Turbulence, Large Eddy Simulation, Cardiovascular Flow, Wall Shear Stress
    National Category
    Fluid Mechanics and Acoustics
    Identifiers
    urn:nbn:se:liu:diva-73211 (URN)
    Available from: 2011-12-22 Created: 2011-12-22 Last updated: 2016-03-14
    3. Quantifying Turbulent Wall Shear Stress in a Stenosed Pipe Using Large Eddy Simulation
    Open this publication in new window or tab >>Quantifying Turbulent Wall Shear Stress in a Stenosed Pipe Using Large Eddy Simulation
    2010 (English)In: Journal of Biomechanical Engineering, ISSN 0148-0731, E-ISSN 1528-8951, Vol. 132, no 6Article in journal (Refereed) Published
    Abstract [en]

    Large eddy simulation was applied for flow of Re = 2000 in a stenosed pipe in order to undertake a thorough investigation of the wall shear stress (WSS) in turbulent flow. A decomposition of the WSS into time averaged and fluctuating components is proposed. It was concluded that a scale resolving technique is required to completely describe the WSS pattern in a subject specific vessel model, since the poststenotic region was dominated by large axial and circumferential fluctuations. Three poststenotic regions of different WSS characteristics were identified. The recirculation zone was subject to a time averaged WSS in the retrograde direction and large fluctuations. After reattachment there was an ante grade shear and smaller fluctuations than in the recirculation zone. At the reattachment the fluctuations were the largest, but no direction dominated over time. Due to symmetry the circumferential time average was always zero. Thus, in a blood vessel, the axial fluctuations would affect endothelial cells in a stretched state, whereas the circumferential fluctuations would act in a relaxed direction.

    Place, publisher, year, edition, pages
    American Society Mechanical Engineers, 2010
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-58347 (URN)10.1115/1.4001075 (DOI)000278965500002 ()
    Available from: 2010-08-13 Created: 2010-08-11 Last updated: 2017-12-12
    4. Quantifying turbulent wall shear stress in a subject specific human aorta using large eddy simulation
    Open this publication in new window or tab >>Quantifying turbulent wall shear stress in a subject specific human aorta using large eddy simulation
    2012 (English)In: Medical Engineering and Physics, ISSN 1350-4533, E-ISSN 1873-4030, Vol. 34, no 8, p. 1139-1148Article in journal (Refereed) Published
    Abstract [en]

    In this study, large-eddy simulation (LES) is employed to calculate the disturbed flow field and the wall shear stress (WSS) in a subject specific human aorta. Velocity and geometry measurements using magnetic resonance imaging (MRI) are taken as input to the model to provide accurate boundary conditions and to assure the physiological relevance. In total, 50 consecutive cardiac cycles were simulated from which a phase average was computed to get a statistically reliable result. A decomposition similar to Reynolds decomposition is introduced, where the WSS signal is divided into a pulsating part (due to the mass flow rate) and a fluctuating part (originating from the disturbed flow). Oscillatory shear index (OSI) is plotted against time-averaged WSS in a novel way, and locations on the aortic wall where elevated values existed could easily be found. In general, high and oscillating WSS values were found in the vicinity of the branches in the aortic arch, while low and oscillating WSS were present in the inner curvature of the descending aorta. The decomposition of WSS into a pulsating and a fluctuating part increases the understanding of how WSS affects the aortic wall, which enables both qualitative and quantitative comparisons.

    Place, publisher, year, edition, pages
    Elsevier, 2012
    Keywords
    Human aorta, Atherosclerosis, Wall shear stress, Computational fluid dynamics, Scale resolving turbulence model, Reynolds decomposition
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-84887 (URN)10.1016/j.medengphy.2011.12.002 (DOI)000309028800016 ()
    Note

    Funding Agencies|Swedish research council|VR 2007-4085VR 2010-4282|National Supercomputer Centre (NSC)|SNIC022/09-11|

    Available from: 2012-11-01 Created: 2012-10-26 Last updated: 2017-12-07
    5. Large Eddy Simulation of Pulsating Flow Before and After CoA Repair - CFD for Intervention Planning
    Open this publication in new window or tab >>Large Eddy Simulation of Pulsating Flow Before and After CoA Repair - CFD for Intervention Planning
    2015 (English)In: Advances in Mechanical Engineering, ISSN 1687-8132, E-ISSN 1687-8140, Vol. 7, no 2Article in journal (Refereed) Published
    Abstract [en]

    Large eddy simulation was applied to investigate hemodynamics in a model with coarctation of the aorta (CoA) and post-stenotic dilatation. Special focus was put on the role of hemodynamics for success of CoA repair. Several parameters previously identified as related to cardiovascular disease were studied. Known risk factors were observed both with CoA and after repair, and the restoration of the anatomy seems to be crucial for a successful result.

    Place, publisher, year, edition, pages
    Hindawi Publishing Corporation / SAGE Publications, 2015
    Keywords
    Coarctation of the Aorta, CFD, Intervention Planning, Turbulence, Wall Shear Stress, Shear Rate
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-100917 (URN)10.1155/2014/971418 (DOI)000354083600087 ()
    Available from: 2013-11-14 Created: 2013-11-14 Last updated: 2017-12-06Bibliographically approved
    Download full text (pdf)
    Turbulent Flow in Constricted Blood Vessels: Quantification ofWall Shear Stress Using Large Eddy Simulation
    Download (pdf)
    omslag
  • 10.
    Gårdhagen, Roland
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Carlsson, Fredrik
    FS Dynamics Sweden AB, Göteborg, Sweden.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Large Eddy Simulation of Pulsating Flow Before and After CoA Repair - CFD for Intervention Planning2015In: Advances in Mechanical Engineering, ISSN 1687-8132, E-ISSN 1687-8140, Vol. 7, no 2Article in journal (Refereed)
    Abstract [en]

    Large eddy simulation was applied to investigate hemodynamics in a model with coarctation of the aorta (CoA) and post-stenotic dilatation. Special focus was put on the role of hemodynamics for success of CoA repair. Several parameters previously identified as related to cardiovascular disease were studied. Known risk factors were observed both with CoA and after repair, and the restoration of the anatomy seems to be crucial for a successful result.

    Download full text (pdf)
    fulltext
  • 11.
    Gårdhagen, Roland
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Carlsson, Fredrik
    ANSYS Sweden, Gothenburg, Sweden.
    Karlsson, Matts
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Large Eddy Simulation of Steady and Pulsating Flow in Asymmetric Stenosed Pipe2010In: ASME 2010 Summer Bioengineering Conference: Parts A and B, The American Society of Mechanical Engineers (ASME) , 2010, p. 573-574Conference paper (Refereed)
    Abstract [en]

    Local hemodynamics and its impact on the development of cardiovascular disease and the blood itself have gained increasing attention during the last decades. Regions with low and/or oscillatory Wall Shear Stress (WSS) have been correlated with increased risk for development of atherosclerosis [1]; and turbulence in the cardio vascular system is suggested to increase the risk for hemolysis as well as platelet activation and thrombus formation [2, 3]. Furthermore, turbulent flows are inherently oscillatory with large spatial as well as temporal fluctuation, and hence possibly a risk for atherosclerosis development per se.

  • 12.
    Gårdhagen, Roland
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Lantz, Jonas
    Tutorial: Creating Geometry and Mesh with ANSYS ICEM 10.02006Report (Other academic)
  • 13.
    Gårdhagen, Roland
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Lantz, Jonas
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Carlsson, Fredric
    FS Dynamics Sweden AB, Gothenburg.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Large Eddy Simulation of Stenotic Flow for Wall Shear Stress Estimation - Validation and Application2011In: WSEAS Transactions on Biology and Biomedicine, ISSN 1109-9518, Vol. 8, no 3, p. 86-101Article in journal (Refereed)
    Abstract [en]

    Turbulent flow in the cardiovascular system may increase the risk for severe arterial disease. This workaddresses the feasibility of Large Eddy Simulation (LES) using a general purpose code as a tool for assessmentof cardiovascular flow and investigates Wall Shear Stress (WSS) in steady as well as pulsating turbulent pipeflow. Poiseuille flow was specified at the inlet, and with a suitable ammount of perturbations at the inlet it waspossible to predict experimental data. The extent of the recirculation zone was affected by the inlet disturbances,and magnitude as well as direction of the WSS vector varied significantly at the reattachment point. For thepulsating flow, WSS shows a complex pattern with different spatial and temporal variation along the pipe. Thewall shear stress gradient was calculated on the entire post-stenotic surface and each component in the gradientwas investigated. The off-diagonal components in the gradient are usually assumed to be small, but here they werefound to be on the same order of magnitude as the diagonal terms. This work demonstrates the need for a scaleresolving simulation technique to accurately model cardiovascular flows.

  • 14.
    Gårdhagen, Roland
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Lantz, Jonas
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Carlsson, Fredrik
    ANSYS Sweden, Gothenburg, Sweden.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Large Eddy Simulation of Flow through a Stenosed Pipe2009In: ASME 2008 Summer Bioengineering Conference, Parts A and B, American Society of Mechanical Engineers , 2009, p. 445-446Conference paper (Refereed)
    Abstract [en]

    A majority of all deaths in the developed world are related to atherosclerosis, i.e. obstruction of blood vessels caused by growth of the vessel wall. Hemodynamic phenomena, especially wall shear stress, are since several decades thought to influence the risk to develop atherosclerosis; hence simulation of blood flow, either in order to elucidate the relation between the hemodynamic and disease initiation or to study the flow pattern, is an area of intense research [1,2].

  • 15.
    Gårdhagen, Roland
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics . Linköping University, The Institute of Technology.
    Lantz, Jonas
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics . Linköping University, The Institute of Technology.
    Carlsson, Fredrik
    ANSYS Sweden.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics . Linköping University, The Institute of Technology.
    Quantifying Turbulent Wall Shear Stress in a Stenosed Pipe Using Large Eddy Simulation2010In: Journal of Biomechanical Engineering, ISSN 0148-0731, E-ISSN 1528-8951, Vol. 132, no 6Article in journal (Refereed)
    Abstract [en]

    Large eddy simulation was applied for flow of Re = 2000 in a stenosed pipe in order to undertake a thorough investigation of the wall shear stress (WSS) in turbulent flow. A decomposition of the WSS into time averaged and fluctuating components is proposed. It was concluded that a scale resolving technique is required to completely describe the WSS pattern in a subject specific vessel model, since the poststenotic region was dominated by large axial and circumferential fluctuations. Three poststenotic regions of different WSS characteristics were identified. The recirculation zone was subject to a time averaged WSS in the retrograde direction and large fluctuations. After reattachment there was an ante grade shear and smaller fluctuations than in the recirculation zone. At the reattachment the fluctuations were the largest, but no direction dominated over time. Due to symmetry the circumferential time average was always zero. Thus, in a blood vessel, the axial fluctuations would affect endothelial cells in a stretched state, whereas the circumferential fluctuations would act in a relaxed direction.

  • 16.
    Gårdhagen, Roland
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Lantz, Jonas
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Carlsson, Fredrik
    ANSYS Sweden.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Wall Shear Stress in Turbulent Pipe Flow2009In: Proceedings of the ASME Summer Bioengineering Conference 2009, 2009, p. 963-964Conference paper (Refereed)
    Abstract [en]

    Low and/or oscillatory Wall Shear Stress (WSS) has been correlated with elevated risk for increased intima media thickness and atherosclerosis in several studies during the last decades [1, 2]. Most of the studies have addressed laminar flows, in which the oscillations mainly are due to the pulsating nature of blood flow. Turbulent flows however show significant spatial and temporal fluctuations although the mean flow is steady.

  • 17.
    Gårdhagen, Roland
    et al.
    Linköping University, Department of Mechanical Engineering. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Renner, Johan
    Linköping University, Department of Mechanical Engineering. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Karlsson, Matts
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Assessment of Geometrical Influence on WSS Estimation in the Human Aorta2006In: WSEAS Transactions on Fluid Mechanics, ISSN 1790-5087, Vol. 4, no 1, p. 318-326Article in journal (Refereed)
    Abstract [en]

    Computational fluid dynamics simulations were performed on a stenosed human aorta with poststenotic dilatation, in order to estimate wall shear stress (WSS). WSS is important due to its correlation with atherosclerosis. Both steady-state and non-stationary simulations were conducted. Three different models were created from a set of MRI images. Comparison of geometrically different models was accomplished by using geometrical landmarks and a comparison parameter. Geometrical differences had larger influence on WSS magnitude than inflow rotation in steady-state results for the models used. In non-stationary flow the largest differences in WSS are found when the flow velocity near the wall is low e.g. when the inflow is low or in recirculation regions.

  • 18.
    Gårdhagen, Roland
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Renner, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Computational Fluid Dynamics CFD TMMV532006Report (Other (popular science, discussion, etc.))
  • 19.
    Gårdhagen, Roland
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Renner, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Computational Fluid Dynamics CFD TMMV53 Course Compendium2006Report (Other (popular science, discussion, etc.))
  • 20.
    Gårdhagen, Roland
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Renner, Johan
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Länne, Toste
    Linköping University, Department of Medicine and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Karlsson, Matts
    Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation. Linköping University, The Institute of Technology.
    Subject Specific Wall Shear Stress in the Human Thoracic Aorta2006In: WSEAS Transaction on biology and biomedicine, ISSN 1109-9518, Vol. 10, no 3, p. 609-614Article in journal (Refereed)
    Abstract [en]

    Numerous studies have shown a correlation between Wall Shear Stress (WSS) and atherosclerosis, but few have evaluated the reliability of estimation methods and measures used to assessWSS, which is the subject of this work. A subject specific vessel model of the aortic arch and thoracic aorta is created fromMRI images and used for CFD simulations with MRI velocity measurements as inlet boundary condition. WSS is computed from the simulation results. Aortic WSS shows significant spatial as well as temporal variation during a cardiac cycle, which makes circumferential values very uninformative, and approximate estimates using Hagen-Poiseuille fails predict the averageWSS. Highly asymmetric flow, especially in the arch, causes the spatial WSS variations.

  • 21.
    Gårdhagen, Roland
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Svensson, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    CFD Analysis of Rotating Flows in Human Aorta2004Report (Other academic)
  • 22.
    Gårdhagen, Roland
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Svensson, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    CFD Studies of Rotating Blood Flows in Human Aorta - A Parameter Estimation2004In: 17th Nordic Seminar on Computational Mechanics,2004, 2004Conference paper (Refereed)
  • 23.
    Gårdhagen, Roland
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Svensson, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Complex Flow Pattern in Realistic Geometry of Human Aorta2004In: 3rd International Conference on Computational Fluid Dynamics ICCFD3,2004, 2004Conference paper (Refereed)
  • 24.
    Gårdhagen, Roland
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Svensson, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Non-Newtonian Effects in Blood Flow Through Constriction and Dillatiation - Steady Flow2005In: Svenska Mekanikdagar 2005,2005, 2005, p. 60-60Conference paper (Refereed)
  • 25.
    Gårdhagen, Roland
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Svensson, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Wall shear stress in a human aorta with constriction and aneurysm - non-newtonian effects for unsteady flows2005In: 2005 Summer Bioengineering Conference,2005, Vail, USA: Summer Bioengineering Conference Committee , 2005, p. 99-Conference paper (Refereed)
  • 26.
    Gårdhagen, Roland
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Svensson, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Non-newtonian effects on wall shear stress in a human aorta with coarctation and dilatation2005In: NBC05 Umeå,2005, Umeå: International federation for medicac and biological engineering IFMBE , 2005, p. 275-Conference paper (Refereed)
  • 27.
    Hällqvist, Robert
    et al.
    Systems Simulation and Concept Design, Saab Aeronautics, Linköping, Sweden.
    Schminder, Jörg
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Eek, Magnus
    Systems Simulation and Concept Design, Saab Aeronautics, Linköping, Sweden.
    Braun, Robert
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, Faculty of Science & Engineering.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Krus, Petter
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, Faculty of Science & Engineering.
    A Novel FMI and TLM-based Desktop Simulator for Detailed Studies of Thermal Pilot Comfort2018In: ICAS congress proceeding, International Council of the Aeronautical Sciences , 2018, article id ICAS2018_0203Conference paper (Other academic)
    Abstract [en]

    Modelling and Simulation is key in aircraft system development. This paper presents a novel, multi-purpose, desktop simulator that can be used for detailed studies of the overall performance of coupled sub-systems, preliminary control design, and multidisciplinary optimization. Here, interoperability between industrially relevant tools for model development and simulation is established via the Functional Mockup Interface (FMI) and System Structure and Parametrization (SSP) standards. Robust and distributed simulation is enabled via the Transmission Line element Method (TLM). The advantages of the presented simulator are demonstrated via an industrially relevant use-case where simulations of pilot thermal comfort are coupled to Environmental Control System (ECS) steadystate and transient performance.

    Download full text (pdf)
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  • 28.
    Karlsson, Matts
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Lantz, Jonas
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Gårdhagen, Roland
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Renner, Johan
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Biofluid Mechanics -LES and FSI2011In: / [ed] B. Skallerud and H.I. Andersson, tapir academic press , 2011, p. 23-28Conference paper (Other academic)
  • 29. Lantz, Jonas
    et al.
    Gårdhagen, Roland
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Tutorial: Creating Geometry and Mesh with ANSYS ICEM 10.02006Report (Other academic)
    Abstract [en]

       

  • 30.
    Lantz, Jonas
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Quantifying turbulent wall shear stress in a subject specific human aorta using large eddy simulation2012In: Medical Engineering and Physics, ISSN 1350-4533, E-ISSN 1873-4030, Vol. 34, no 8, p. 1139-1148Article in journal (Refereed)
    Abstract [en]

    In this study, large-eddy simulation (LES) is employed to calculate the disturbed flow field and the wall shear stress (WSS) in a subject specific human aorta. Velocity and geometry measurements using magnetic resonance imaging (MRI) are taken as input to the model to provide accurate boundary conditions and to assure the physiological relevance. In total, 50 consecutive cardiac cycles were simulated from which a phase average was computed to get a statistically reliable result. A decomposition similar to Reynolds decomposition is introduced, where the WSS signal is divided into a pulsating part (due to the mass flow rate) and a fluctuating part (originating from the disturbed flow). Oscillatory shear index (OSI) is plotted against time-averaged WSS in a novel way, and locations on the aortic wall where elevated values existed could easily be found. In general, high and oscillating WSS values were found in the vicinity of the branches in the aortic arch, while low and oscillating WSS were present in the inner curvature of the descending aorta. The decomposition of WSS into a pulsating and a fluctuating part increases the understanding of how WSS affects the aortic wall, which enables both qualitative and quantitative comparisons.

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  • 31.
    Lantz, Jonas
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Wren, Joakim
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Heating in a Stenosed Coronary Artery With Pulsating Flow and Non-Newtonian Viscosity2009In: ASME 2008 Summer Bioengineering Conference: Parts A and B, The American Society of Mechanical Engineers (ASME) , 2009, no PART A, p. 331-332Conference paper (Refereed)
    Abstract [en]

    Cardiovascular disease is the most prevalent cause of death in the developed countries and most deaths are due to coronary atherosclerosis [1]. During the development of atherosclerosis, several stages can be distinguished including vulnerable plaque. This group of plaque has an inclination for erosion and rupture and is therefore of particular interest. Due to the inflammatory response of vulnerable plaque including an increased metabolism and thereby a locally increased temperature, it is possible to detect such warm cores by intracoronally temperature measurement under some prerequisitions. Temperature differences up to 2.2 K on the surface of carotid plaques have been measured [2], but the relation between plaque vulnerability, inflammatory response, temperature increase and possibility to detection by means of temperature measurement is far from fully perceived.

  • 32.
    Modin, Daniel
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Renner, Johan
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, The Institute of Technology.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, The Institute of Technology.
    Ebbers, Tino
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Thoracic and Vascular Surgery.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, The Institute of Technology.
    Evaluation of Aortic Geometries created by MRI Data in Man2011In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 31, no 6, p. 485-491Article in journal (Refereed)
    Abstract [en]

    The development of atherosclerotic plaques has been associated with the patterns of wall shear stress (WSS). However, much is still uncertain with the methods used to calculate WSS. Correct vessel geometries are mandatory to get reliable estimations and the purpose of this study was to evaluate an in vivo method for creating aortic 3D geometry in man based on data from magnetic resonance imaging (MRI) with ultrasound as reference.

    Methods: The aortas of ten healthy males, 23.4 ± 1.6 years of age, were examined with MRI, and 3D geometries were created with manual segmentation of the images. Lumen diameters (LD) were measured in the abdominal aorta (AA) and the thoracic aorta (TA) with non-invasive B-mode ultrasound as a reference.

    Results: The anteroposterior diameter of the AA was 13.6 ± 1.1 mm for the MRI and 13.8 ± 1.3 mm for the ultrasound (NS). Intraobserver variability (CV) for MRI and ultrasound was <0.92% and <0.40% respectively . Interobserver variability MRI and ultrasound was 0.96% and 0.56% respectively. The diameter of the TA was 19.2 ± 1.4 mm for the MRI, and the intraobserver variability (CV) were <0.78% and interobserver variability (CV) were 0.92%.

    Conclusion: Specific arterial geometries can be constructed with a high degree of accuracy using MRI. This indicate that the MRI geometries may be used to create realistic and correct geometries in the calculation of WSS in the aorta of man.

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  • 33.
    Nadali Najafabadi, Hossein
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Farhanieh, Arman
    Linköping University, Department of Management and Engineering. Linköping University, Faculty of Science & Engineering.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    On the Characteristics of the Jet in Film Cooling Applications2016In: PROCEEDINGS OF THE 5TH INTERNATIONAL CONFERENCE ON JETS, WAKES AND SEPARATED FLOWS (ICJWSF2015), SPRINGER INT PUBLISHING AG , 2016, Vol. 185, p. 449-455Conference paper (Refereed)
    Abstract [en]

    Numerical and experimental investigations are conducted to study the jet characteristics on the pressure side of a film-cooled turbine guide vane. CFD simulations, including both the steady RANS turbulence model, k - omega shear stress transport (SST), as well as the hybrid approach, Scale-Adaptive Simulation (SAS), are utilized to comprehend the turbulent flow structures and the vortex dynamics associated to the film cooling jet. For this purpose the commercial CFD code FLUENT has been utilized to study flow with injection of coolant through fan-shaped holes for two blowing ratios (0.6 and 1.2). Although, both turbulence models predict the vortical structures and jet dynamics similarly, the findings suggest that by resolving large energy containing vortices, the SAS model can improve the modeling of mixing properties and thereby approximation of the surface temperature.

  • 34.
    Petersson, Sven
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences.
    Dyverfeldt, Petter
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Ebbers, Tino
    Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics.
    Simulation of phase contrast MRI of turbulent flow2010In: Magnetic Resonance in Medicine, ISSN 0740-3194, E-ISSN 1522-2594, Vol. 64, no 4, p. 1039-1046Article in journal (Refereed)
    Abstract [en]

    Phase contrast MRI is a powerful tool for the assessment of blood flow. However, especially in the highly complex and turbulent flow that accompanies many cardiovascular diseases, phase contrast MRI may suffer from artifacts. Simulation of phase contrast MRI of turbulent flow could increase our understanding of phase contrast MRI artifacts in turbulent flows and facilitate the development of phase contrast MRI methods for the assessment of turbulent blood flow. We present a method for the simulation of phase contrast MRI measurements of turbulent flow. The method uses an Eulerian-Lagrangian approach, in which spin particle trajectories are computed from time-resolved large eddy simulations. The Bloch equations are solved for each spin for a frame of reference moving along the spins trajectory. The method was validated by comparison with phase contrast MRI measurements of velocity and intravoxel velocity standard deviation (IVSD) on a flow phantom consisting of a straight rigid pipe with a stenosis. Turbulence related artifacts, such as signal drop and ghosting, could be recognized in the measurements as well as in the simulations. The velocity and the IVSD obtained from the magnitude of the phase contrast MRI simulations agreed well with the measurements.

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  • 35.
    Renner, Johan
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, The Institute of Technology.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, The Institute of Technology.
    Ebbers, Tino
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Heiberg, Einar
    Department of Clinical Physiology, Lund University Hospital, Sweden.
    Länne, Toste
    Linköping University, Department of Medicine and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, The Institute of Technology.
    A method for subject specific estimation of aortic wall shear stress2009In: WSEAS Transactions on Biology and Biomedicine, ISSN 1109-9518, Vol. 6, no 3, p. 49-57Article in journal (Refereed)
    Abstract [en]

    Wall shear stress (WSS) distribution in the human aorta is a highly interesting hemodynamic factor for atherosclerosis development. We present a magnetic resonance imaging (MRI) and computational fluid dynamics (CFD) based subject specific WSS estimation method and demonstrate it on a group of nine healthy volunteers (males age 23.6 ± 1.3 years). In all nine subjects, the aortic blood flow was simulated in a subject specific way, where the 3D segmented geometries and inflow profiles were obtained using MRI. No parameter settings were tailored using data from the nine subjects. Validation was performed by comparing CFD gained velocity with magnetic resonance imaging (MRI) velocity measurements. CFD and MRI velocity profiles were comparable, but the temporal variations of the differences during the cardiac cycle were significant. Spatio-temporal analyzes on the WSS distribution showed a strong subject specific influence. Subject specific models are decisive to estimate WSS distribution.

  • 36.
    Renner, Johan
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Gårdhagen, Roland
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Heiberg, Einar
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology.
    Ebbers, Tino
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care.
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Validation of Simulated Velocity of Blood in Patient Specific Aorta2006In: VIII Svenska Kardiovaskulära Vårmöte,2006, Linköping, Sweden: Linköpings universitet , 2006Conference paper (Refereed)
  • 37.
    Renner, Johan
    et al.
    Linköping University, Department of Mechanical Engineering. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Gårdhagen, Roland
    Linköping University, Department of Mechanical Engineering. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Karlsson, Matts
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Post-Processing Dynamic Behavior of WSS in Aortic Blood Flow2006Report (Other academic)
    Abstract [en]

    Pulsating flow simulations with CFD is performed on a stenosed human aorta with post-stenotic dilatation, for development of wall shear stress (WSS) dynamic parameters. WSS is of interest due to its correlation with atherosclerosis. The dynamic behavior and dynamic capturing parameters of WSS are usable in analyzing non-stationary results from blood flow simulations. The amount of wall back-flow is shown to be an very easy parameter to interpret and it showed an "washout" effect in the post-stenotic dilatation. A new dynamic capturing parameter describing the WSS angular amplitude (WSSAA) is presented. It has both differences and similarities with the widely used oscillating shear index (OSI) parameter. WSSA have a more direct physical interpretation then OSI.

  • 38.
    Renner, Johan
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Subject Specific In-Vivo CFD Estimated Aortic WSS: Comparison Between Manual and Automated Segmentation Methods2009In: ASME 2008 Summer Bioengineering Conference: Parts A and B, The American Society of Mechanical Engineers (ASME) , 2009, no PART A, p. 425-426Conference paper (Refereed)
    Abstract [en]

    When making computational fluid dynamics (CFD) based estimations of wall shear stress (WSS) in the human aorta, medical image converting processes to 3D geometries are important as the result is strongly dependent on the quality of the geometry [1]. The image interpretation process or segmentation can be more or less automated; however in clinical work today the gold standard is to manually interpret the medical image information. This combined magnetic resonance imaging (MRI) and CFD method aims to estimate WSS in human arteries in-vivo as WSS is strongly linked to atherosclerosis [2]. More or less automated segmentation has been used in previous studies but normally based on a stack of 2D individually segmented slices which is combined into a 3D model [3]. The aim of this work is to compare manual 2D and automatic 3D segmentations.

  • 39.
    Schminder, Jörg
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    A generic simulation model for prediction of thermal conditions and human performance in cockpits2018In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 143, p. 120-129Article in journal (Refereed)
    Abstract [en]

    This paper presents a computational approach to predict the thermal environment in a cockpit during on-ground and in-flight aircraft operation. A method was developed to model cockpit air temperature, which serves as input to black-globe and wet-bulb temperature computation. Subsequently the simulated temperatures are used to compute common heat stress indices such as Wet Bulb Globe Temperature (WBGT), Fighter Index of Thermal Stress (FITS), or Predicted Mean Vote (PMV). To demonstrate the manifold information made available by the computed heat stress indices, WBGT e.g. is set in relation to different types of occupational exposure limits demonstrating not only the possibility to predict physiological constraints but mental performance too. The generic cockpit model and thermal comfort computations were validated against experimental data gained from on ground temperature measurements inside an aircraft cockpit, which underwent a sudden large temperature change. The results exemplify how thermal comfort and possible physical as well as mental degradation of aircrews can be assessed quickly using the presented model.

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  • 40.
    Schminder, Jörg
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Nilsson, Elias
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Storck, Karl
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering. SAAB Dynamics AB, Linköping, Sweden.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Development of a Cockpit-Pilot Model for Thermal Comfort Optimization During Long-Mission Flight2016In: AIAA Modeling and Simulation Technologies Conference San Diego, California, USA, AAAI Press, 2016Conference paper (Refereed)
    Abstract [en]

    The thermal comfort of a pilot is of crucial importance to maintain a high level ofconcentration and awareness during the entire ight mission. In this work a model for thethermal environment of the cockpit is developed and used as provider of input parametersto a thermoregulatory model, adopted from the literature, of a human. The cockpit-pilotmodel will be used to investigate and improve the thermal comfort for the pilot, particularlyduring longer ight missions. In the cockpit model a combination of lumped systems and nite dierence calculationsis used to obtain input parameters, which are provided to the pilot model. The body, withclothes, is divided into 16 segments and a nite dierence method is used to determine thetemperature distribution within these. Several physiological mechanisms are included inthe model. Simulations with dierent boundary conditions show that the models work properlyeven for longer missions.

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  • 41.
    Schminder, Jörg
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Hällqvist, Robert
    Systems Simulation and Concept Design, Saab Aeronautics, Linköping, Sweden.
    Eek, Magnus
    Systems Simulation and Concept Design, Saab Aeronautics, Linköping, Sweden.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    PILOT PERFORMANCE AND HEAT STRESS ASSESSMENT SUPPORT USING A COCKPIT THERMOREGULATORY SIMULATION MODEL2018In: ICAS congress proceeding, International Council of the Aeronautical Sciences , 2018, article id ICAS2018_0463Conference paper (Other academic)
    Abstract [en]

    Flights with high thermal loads inside the cockpit can have a considerable impact on pilot physiological and psychological performance resulting in thermal discomfort, dehydration and fatigue. In this work, a Functional Mock-up Interface (FMI) based aircraft system simulator is utilized with intent to compute and predict thermal comfort. The simulator can for example serve pilots as a tool for heat stress and flight risk assessment, supporting their pre-flight planning or be used by engineers to design and optimize cooling efficiency during an early aircraft design phase. Furthermore, the presented simulator offers several advantages such as map based thermal comfort analysis for a complete flight envelop, time resolved mental performance prediction, and a flexible composability of the included models.

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  • 42.
    Schminder, Jörg
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Nadali Najafabadi, Hossein
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Learning by teaching: Student developed material for self-directed studies2016In: The 12th International CDIO Conference: Proceedings - Full Papers, Turku: Turku University of Applied Sciences , 2016, p. 750-759Conference paper (Refereed)
    Abstract [en]

    The objective of the presented paper is to demonstrate how e-learning course material developed by the students can enhance active learning for self-directed studies outside the classroom in a flipped classroom concept. A method which merges different learning activities such as learning by teaching, video based teaching etc. was developed to improve the students’ personal and interpersonal engineering skills in relation to CDIO standards. In an effort to assess the students’ satisfaction and practical use of the students’ created material, a survey was conducted. Statistics, the students’ feedback, and observations show an increase in learning motivation, deepened understanding, and expanded communication skills.

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  • 43. Svensson, J.
    et al.
    Gårdhagen, Roland
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, M.
    Assessment of Geometrical Influence on WSS Estimation in the Human Aorta2006In: WSEAS Transactions on Fluid Mechanics, 2006, Vol. 1Conference paper (Refereed)
    Abstract [en]

    Computational fluid dynamics simulations were performed on a stenosed human aorta with poststenotic dilatation, in order to estimate wall shear stress (WSS). WSS is important due to its correlation with atherosclerosis. Both steady-state and non-stationary simulations were conducted. Three different models were created from a set of MRI images. Comparison of geometrically different models was accomplished by using geometrical landmarks and a comparison parameter. Geometrical differences had larger influence on WSS magnitude than inflow rotation in steady-state results for the models used. In non-stationary flow the largest differences in WSS are found when the flow velocity near the wall is low e.g. when the inflow is low or in recirculation regions.

  • 44.
    Svensson, Johan
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Gårdhagen, Roland
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Comparison of flow parameters between different geometries of a human aorta with coarctation and aneurysm2005In: 2005 Summer Bioengineering Conference,2005, Vail, USA: Summer Bioengineering Conference Committee , 2005Conference paper (Refereed)
  • 45.
    Svensson, Johan
    et al.
    Linköping University, Department of Mechanical Engineering. Linköping University, The Institute of Technology.
    Gårdhagen, Roland
    Linköping University, Department of Mechanical Engineering. Linköping University, The Institute of Technology.
    Karlsson, Matts
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Geometrical Considerations in Patient Specific Models of a Human Aorta with Stenosis and Aneurysm2004In: Computational Fluid Dynamics 2004: Proceedings of the Third International Conference on Computational Fluid Dynamics, ICCFD3, Toronto, 12–16 July 2004, 2004, p. 335-340Conference paper (Refereed)
    Abstract [en]

    The most important artery in the human body is the aorta that supplies the rest of the body with blood. Lesions in the aorta can cause serious complications, which can even lead to death. How the flow is behaving in lesions, what causes the problems and which lesions are dangerous are highly interesting to determine. Laminar, stationary CFD calculations are performed on two geometrically different models of the human aorta created from the same set of patient MRI (Magnetic Resonance Imaging) data. Differences in the CFD results due to different geometries are evaluated. Overview results e.g. pressure variations throughout the artery are not dependent on an exact description of the geometry. If absolute and local values e.g. wall shear stress are sought more robust geometry creation procedure is needed in order to get more reliable results.

  • 46.
    Svensson, Johan
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Gårdhagen, Roland
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Geometrical Influence on CFD Analysis of Human Aorta2004Report (Other academic)
  • 47.
    Svensson, Johan
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Gårdhagen, Roland
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Patient Specific Human Aorta Geometry Influence on CFD Simulation Parameters2004In: 17th Nordic Seminar on Computational Mechanics NSCM17,2004, 2004Conference paper (Refereed)
  • 48.
    Svensson, Johan
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Gårdhagen, Roland
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Wall Back Flow Variations During Pulsative Flow in a Human Aorta2005In: Svenska Mekanikdagar 2005,2005, 2005, p. 61-62Conference paper (Refereed)
  • 49.
    Svensson, Johan
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Gårdhagen, Roland
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Wall back flow in human aorta: influence of geometry2005In: NBC05 Umeå,2005, Umeå: Int'l federation for medical anc Biological Engineering IFMBE , 2005, p. 85-Conference paper (Refereed)
  • 50.
    Svensson (Renner), Johan
    et al.
    Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Gårdhagen, Roland
    Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Heiberg, Einar
    Department of Clinical Physiology, Lund University, Sweden.
    Ebbers, Tino
    Linköping University, Department of Medicine and Care. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Loyd, Dan
    Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Länne, Toste
    Linköping University, Department of Medicine and Care, Physiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Karlsson, Matts
    Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Feasibility of Patient Specific Aortic Blood Flow CFD Simulation2006In: Medical Image Computing and Computer-Assisted Intervention – MICCAI 2006: 9th International Conference, Copenhagen, Denmark, October 1-6, 2006. Proceedings, Part I / [ed] Rasmus Larsen, Mads Nielsen and Jon Sporring, Springer Berlin/Heidelberg, 2006, 1, Vol. 4190, p. 257-263Conference paper (Refereed)
    Abstract [en]

    Patient specific modelling of the blood flow through the human aorta is performed using computational fluid dynamics (CFD) and magnetic resonance imaging (MRI). Velocity patterns are compared between computer simulations and measurements. The workflow includes several steps: MRI measurement to obtain both geometry and velocity, an automatic levelset segmentation followed by meshing of the geometrical model and CFD setup to perform the simulations follwed by the actual simulations. The computational results agree well with the measured data.

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