liu.seSearch for publications in DiVA
Change search
Link to record
Permanent link

Direct link
BETA
Publications (10 of 49) Show all publications
Hällqvist, R., Schminder, J., Eek, M., Braun, R., Gårdhagen, R. & Krus, P. (2018). A Novel FMI and TLM-based Desktop Simulator for Detailed Studies of Thermal Pilot Comfort. In: ICAS congress proceeding: . Paper presented at 31st Congress of the International Council of the Aeronautical Sciences,Belo Horizonte, Brazil, September 9-14, 2018. International Council of the Aeronautical Sciences, Article ID ICAS2018_0203.
Open this publication in new window or tab >>A Novel FMI and TLM-based Desktop Simulator for Detailed Studies of Thermal Pilot Comfort
Show others...
2018 (English)In: ICAS congress proceeding, International Council of the Aeronautical Sciences , 2018, article id ICAS2018_0203Conference paper, Published 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.

Place, publisher, year, edition, pages
International Council of the Aeronautical Sciences, 2018
Keywords
OMSimulator; FMI; TLM; Pilot Thermal Comfort; Modelling and Simulation
National Category
Applied Mechanics Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-152897 (URN)9783932182884 (ISBN)
Conference
31st Congress of the International Council of the Aeronautical Sciences,Belo Horizonte, Brazil, September 9-14, 2018
Available from: 2018-11-27 Created: 2018-11-27 Last updated: 2020-01-16Bibliographically approved
Alfredson, J., Johansson, B., Gonzaga Trabasso, L., Schminder, J., Granlund, R. & Gårdhagen, R. (2018). DESIGN OF A DISTRIBUTED HUMAN FACTORS LABORATORY FOR FUTURE AIRSYSTEMS. In: ICAS congress proceeding: . Paper presented at 31st Congress of the International Council of the Aeronautical Sciences,Belo Horizonte, Brazil, September 9-14, 2018. International Council of the Aeronautical Sciences, Article ID ICAS2018_0305.
Open this publication in new window or tab >>DESIGN OF A DISTRIBUTED HUMAN FACTORS LABORATORY FOR FUTURE AIRSYSTEMS
Show others...
2018 (English)In: ICAS congress proceeding, International Council of the Aeronautical Sciences , 2018, article id ICAS2018_0305Conference paper, Published 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.

Place, publisher, year, edition, pages
International Council of the Aeronautical Sciences, 2018
Keywords
Human Factors; Future Air Systems; Laboratory
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:liu:diva-152898 (URN)978-3-932182-88-4 (ISBN)
Conference
31st Congress of the International Council of the Aeronautical Sciences,Belo Horizonte, Brazil, September 9-14, 2018
Available from: 2018-11-27 Created: 2018-11-27 Last updated: 2018-11-27
Schminder, J., Hällqvist, R., Eek, M. & Gårdhagen, R. (2018). PILOT PERFORMANCE AND HEAT STRESS ASSESSMENT SUPPORT USING A COCKPIT THERMOREGULATORY SIMULATION MODEL. In: ICAS congress proceeding: . Paper presented at 31st Congress of the International Council of the Aeronautical Sciences,Belo Horizonte, Brazil, September 9-14, 2018. International Council of the Aeronautical Sciences, Article ID ICAS2018_0463.
Open this publication in new window or tab >>PILOT PERFORMANCE AND HEAT STRESS ASSESSMENT SUPPORT USING A COCKPIT THERMOREGULATORY SIMULATION MODEL
2018 (English)In: ICAS congress proceeding, International Council of the Aeronautical Sciences , 2018, article id ICAS2018_0463Conference paper, Published 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.

Place, publisher, year, edition, pages
International Council of the Aeronautical Sciences, 2018
Keywords
Thermal Comfort; Heat Stress;Thermoregulatory Model;Modeling and Simulation
National Category
Aerospace Engineering
Identifiers
urn:nbn:se:liu:diva-152900 (URN)978-3-932182-88-4 (ISBN)
Conference
31st Congress of the International Council of the Aeronautical Sciences,Belo Horizonte, Brazil, September 9-14, 2018
Available from: 2018-11-27 Created: 2018-11-27 Last updated: 2020-01-16
Ekman, P., Gårdhagen, R., Virdung, T. & Karlsson, M. (2016). Aerodynamic Drag Reduction of a Light Truck - from Conceptual Design to Full Scale Road Tests. In: SAE 2016 World Congress and Exhibition: . Paper presented at SAE 2016 World Congress and Exhibition. SAE International
Open this publication in new window or tab >>Aerodynamic Drag Reduction of a Light Truck - from Conceptual Design to Full Scale Road Tests
2016 (English)In: SAE 2016 World Congress and Exhibition, SAE International , 2016Conference paper, Published 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.

Place, publisher, year, edition, pages
SAE International, 2016
National Category
Vehicle Engineering
Identifiers
urn:nbn:se:liu:diva-164923 (URN)10.4271/2016-01-1594 (DOI)
Conference
SAE 2016 World Congress and Exhibition
Available from: 2020-04-02 Created: 2020-04-02 Last updated: 2020-04-02Bibliographically approved
Schminder, J., Gårdhagen, R., Nilsson, E., Storck, K. & Karlsson, M. (2016). Development of a Cockpit-Pilot Model for Thermal Comfort Optimization During Long-Mission Flight. In: AIAA Modeling and Simulation Technologies Conference San Diego, California, USA: . Paper presented at SciTech 2016,AIAA Modeling and Simulation Technologies Conference San Diego, California, USA. AAAI Press
Open this publication in new window or tab >>Development of a Cockpit-Pilot Model for Thermal Comfort Optimization During Long-Mission Flight
Show others...
2016 (English)In: AIAA Modeling and Simulation Technologies Conference San Diego, California, USA, AAAI Press, 2016Conference paper, Published 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.

Place, publisher, year, edition, pages
AAAI Press, 2016
Keywords
Aircraft, Cockpit, Pilot, Thermal Comfort, Modelling, Environmental Control System, ECS
National Category
Aerospace Engineering Transport Systems and Logistics
Identifiers
urn:nbn:se:liu:diva-126538 (URN)10.2514/6.2016-0172 (DOI)
Conference
SciTech 2016,AIAA Modeling and Simulation Technologies Conference San Diego, California, USA
Available from: 2016-03-30 Created: 2016-03-30 Last updated: 2018-07-18
Schminder, J., Nadali Najafabadi, H. & Gårdhagen, R. (2016). Learning by teaching: Student developed material for self-directed studies. In: The 12th International CDIO Conference: Proceedings - Full Papers. Paper presented at 12th International CDIO Conference, Turku, Finland, June 12-16, 2016 (pp. 750-759). Turku: Turku University of Applied Sciences
Open this publication in new window or tab >>Learning by teaching: Student developed material for self-directed studies
2016 (English)In: The 12th International CDIO Conference: Proceedings - Full Papers, Turku: Turku University of Applied Sciences , 2016, p. 750-759Conference paper, Published 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.

Place, publisher, year, edition, pages
Turku: Turku University of Applied Sciences, 2016
Series
Research Reports from Turku University of Applied Sciences, ISSN 1796-9964 ; 45
Keywords
Learning by Teaching, Video, Multimedia, Lisam, Flipped Classroom, E-learning
National Category
Pedagogical Work
Identifiers
urn:nbn:se:liu:diva-129455 (URN)978-952-216-610-4 (ISBN)
Conference
12th International CDIO Conference, Turku, Finland, June 12-16, 2016
Available from: 2016-06-20 Created: 2016-06-20 Last updated: 2017-06-01Bibliographically approved
Ekman, P., Gårdhagen, R., Virdung, T. & Karlsson, M. (2015). Aerodynamic Drag Reduction - from Conceptual Design on a Simplified Generic Model to Full-Scale Road Tests. In: SAE 2015 World Congress & Exhibition: . Paper presented at SAE 2015 World Congress & Exhibition. SAE International
Open this publication in new window or tab >>Aerodynamic Drag Reduction - from Conceptual Design on a Simplified Generic Model to Full-Scale Road Tests
2015 (English)In: SAE 2015 World Congress & Exhibition, SAE International , 2015Conference paper, Published 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%.

Place, publisher, year, edition, pages
SAE International, 2015
National Category
Vehicle Engineering
Identifiers
urn:nbn:se:liu:diva-164920 (URN)10.4271/2015-01-1543 (DOI)
Conference
SAE 2015 World Congress & Exhibition
Available from: 2020-04-02 Created: 2020-04-02 Last updated: 2020-04-02Bibliographically approved
Gårdhagen, R., Carlsson, F. & Karlsson, M. (2015). Large Eddy Simulation of Pulsating Flow Before and After CoA Repair - CFD for Intervention Planning. Advances in Mechanical Engineering, 7(2)
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
Gårdhagen, R. (2013). Turbulent Flow in Constricted Blood Vessels: Quantification of Wall Shear Stress Using Large Eddy Simulation. (Doctoral dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Turbulent Flow in Constricted Blood Vessels: Quantification of Wall Shear Stress Using Large Eddy Simulation
2013 (English)Doctoral 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.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2013. p. 57
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1558
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-100918 (URN)10.3384/diss.diva-100918 (DOI)978-91-7519-473-8 (ISBN)
Public defence
2013-12-10, C3, hus C, Campus Valla, Linköpings universitet, Linköping, 10:15 (English)
Opponent
Supervisors
Available from: 2013-11-14 Created: 2013-11-14 Last updated: 2019-12-03Bibliographically approved
Bradley, A., Gårdhagen, R. & Karlsson, M. (2012). Bird-Like Wing Conguration for Pitch Control of a Tailless Aircraft. In: : . Paper presented at 50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition.
Open this publication in new window or tab >>Bird-Like Wing Conguration for Pitch Control of a Tailless Aircraft
2012 (English)Conference paper, Published 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.

Keywords
Aerodynamics, Conceptual design, CFD
National Category
Aerospace Engineering
Identifiers
urn:nbn:se:liu:diva-75568 (URN)10.2514/6.2012-248 (DOI)
Conference
50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition
Available from: 2012-03-08 Created: 2012-03-08 Last updated: 2016-03-14
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-6634-797X

Search in DiVA

Show all publications