http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Simone Sebben (검색결과 5 건)
- 무료
- 기관 내 무료
- 유료
-
Influence of Inter-Vehicle Distance on the Aerodynamics of a Two-Truck Platoon
Törnell Johannes,Sebben Simone,Söderblom David 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.3
The increasing importance of fuel and energy efficiency in transport combined with recent improvements in vehicle automation has renewed interest in the concept of platooning. Many studies so far have used very simplified models, thus, creating a need for understanding the flow behavior and the aerodynamic gains in more complex scenarios. This paper proposes a method of examining the aerodynamics of vehicles driving in close proximity using detailed European truck models and Computational Fluid Dynamics. The study was conducted using two trucks driving at intervehicle distances of 2.5 m to 20 m. A thorough numerical investigation was carried out and showed that the combined drag of the platoon had a continuous improvement with decreased distance between the vehicles. This was due to a significant drag improvement of the leading truck. This behavior originated from the increased base pressure induced by the presence of a close blockage behind it. The drag of the trailing truck showed an opposite behavior, that is, a moderate increase in drag with decreased inter-vehicle distance. This was a result of a decreased acceleration of the flow around the front edges and an increase in pressure in the tractor-trailer gap.
-
Emil Ljungskog,Simone Sebben,Alexander Broniewicz,Christoffer Landström 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6
Computational fluid dynamics (CFD) is an important and extensively used tool for aerodynamic development in the vehicle industrytoday. Validation of virtual methods by comparison to wind tunnel experiments is a must because manufacturers aim to substitute physicaltests on prototype vehicles with virtual simulations. An appropriate validation can be performed only if the wind tunnel geometrywith representative boundary conditions is included in the numerical simulation, and if the flow of the empty wind tunnel is accuratelypredicted. One of the important flow parameters to predict is the longitudinal pressure distribution in the test section, which is dependenton both the wind tunnel geometry and the settings of the boundary layer control systems. This study investigates the effects of flow angularityat the inlet and different boundary layer control systems, namely, basic scoop suction, distributed suction, and moving belts, on thelongitudinal pressure distribution in the full-scale aerodynamic wind tunnel of Volvo Cars using CFD and a systematic design of experimentsapproach. The study shows that the different suction systems used to reduce boundary layer thickness upstream of the vehicle havestatistically significant effects on the longitudinal pressure distribution in the test section. However, the estimated drag difference inducedon a typical vehicle by the difference in horizontal buoyancy between the tested settings is within the test-to-test uncertainty of the physicalwind tunnel, thereby leading to the conclusion that force calculations in simulations are fairly insensitive to the tested parameters onthe investigated intervals.
-
NUMERICAL INVESTIGATION OF THE AIR FLOW IN A SIMPLIFIED UNDERHOOD ENVIRONMENT
Randi Franzke,Simone Sebben,Emil Willeson 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.6
Thermal management plays a crucial role for the energy efficiency of electrified vehicles. Using numerical flow simulations, the air paths and temperature distributions in the underhood can be identified and optimised early in the development process. However, the numerical method needs to be verified in its accuracy for capturing the important flow features in the underhood. In this study, a numerical approach is developed that is robust with respect to spatial and temporal resolutions as well as to different turbulence models. The methodology is validated against experimental data from LDA measurements. The geometric configurations investigated are representative of electrified vehicles, with one or two front opening designs, two different fans, and with or without a blockage behind. The results showed that for one of the fan installations, although the major flow field structures were well captured, the locations of the peak velocities did not match the experiments. For the second fan, the CFD results agreed well with the measurements.
-
EFFECTS OF WHEEL CONFIGURATION ON THE FLOW FIELD AND THE DRAG COEFFICIENT OF A PASSENGER VEHICLE
Michael Donald Peter Bolzon,Simone Sebben,Alexander Broniewicz 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.4
The effects of wheel rotation, rim coverage area, fan spokes, spoke sharpness, and tread pattern on the flow field and drag coefficient of a passenger vehicle were investigated. Force measurements and wake surveys were taken on a 1/ 5th scale passenger vehicle at a Reynolds number of 2.0 × 106. The wake surveys were conducted at three planes. Vorticity, total pressure coefficient, and local drag coefficient plots are presented. Wheel rotation reduced the drag coefficient of all of the wheel configurations tested, which generally agrees with literature. Wheel rotation reduced the front wheel’s jetting vortex’s drag while increasing the drag from the center of the front wheel to the upper rim track. Reducing the rim coverage area increased the drag coefficient. This increase was attributed to an increased jetting vortex drag and a change in flow separation around the front wheel. The fan spoke rim performed the worst, regardless of rotation. Rounding the spoke edges reduced the drag coefficient of a rotating wheel. The tread pattern slightly reduced the shoulder vortex vorticity and slightly increased the separation around the front wheel.
-
Kumar Arun,Sällström Erik,Sebben Simone,Jacobson Bengt 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.6
In vehicle development, rating vehicle reactions to external disturbances such as aerodynamic excitations are important for improving safety and comfort of passengers. Vehicle motion reactions under such conditions are dependent on both disturbance and drivers’ steering actions. A predictive model has been developed to correctly anticipate the drivers’ ability to identify unexpected external disturbances for straight-line, high-speed driving in a driving simulator. The measured variables were band-pass filtered to desired frequency ranges. Excess yaw and roll velocities, defined as the difference between actual rotations and rotations predicted with a dynamic model from the cause of actual steering, were calculated. The standard deviations of the measured variables in a time window around disturbances were used in a regression model to predict the driver responses. Replacing actual rotations with excess rotations reduced the importance of steering input as a predictor by approximately 2/3, thus improving the accuracy of the predictive model. The model showed the change in driver sensitivity to rotations at different frequency intervals. It also showed that only driver input in around 1 ~ 2 Hz reduces driver sensitivity and that drivers are not necessarily sensitive to high rotational accelerations, but rather to large differences between actual vehicle yaw and roll and expected vehicle yaw and roll responses from the steering input The result from this study were later compared to succeeding on-road tests which confirmed that the predictive model was improved with the use of excess motion variables.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
