scholarly journals Design and aerodynamic analysis of an Automotive Adaptive Rear Diffuser

2021 ◽  
Vol 9 (8) ◽  
pp. 1611-1626
Author(s):  
Heet Patel
Keyword(s):  
Fuel Economy ◽  
High Speed ◽  
Electronic Circuit ◽  
Aerodynamic Drag ◽  
Vital Role ◽  
Aerodynamic Forces ◽  
Aerodynamic Efficiency ◽  
Speed Stability ◽  
Diffuser Angle ◽  
Aerodynamic Lift

Abstract: Traditional vehicles are designed to bring out the best performance, good fuel economy, fewer emissions, and good high-speed stability. In this process of designing a vehicle, the underbody geometry of a car plays a vital role and is often neglected because of its complicated design bits. Though the presence of uneven surfaces causes the layers of air to separate resulting in generating turbulence. This report is about designing an active rear diffuser of a car. The rear diffuser is an aerodynamic device that is installed in the end part of the underbody of a car. Diffuser now a day is quite a common aerodynamic device that is used in performance cars. The main moto of attaching a diffuser is to reduce the wake produced behind the car and help the streamlines to converge better. The prime focus of this study is to design an active rear diffuser that will not only help in providing great high-speed stability and aerodynamic efficiency but will also use the aerodynamic forces adversely to help the car stop faster and on its track. This is made possible first by understanding the effects of diffuser angle on the aerodynamic forces acting on the car. Further, to actually transform the computational values into a working model, an electronic circuit is designed which mimics the exact movement of the diffuser according to the speed and other driving conditions. Keywords: Adaptive, diffuser, automobile, aerodynamic, aerodynamic Drag, aerodynamic Lift

Study on high-speed stability of automobile based on aerodynamic lift feedback

2021 ◽  
Vol 10 (3) ◽  
pp. 293
Author(s):  
Shuichang Liu ◽  
Fengzhao Mao ◽  
Qibo Lin ◽  
Ye Xiao ◽  
Jiaqi Shi ◽  
...  
Keyword(s):  
High Speed ◽  
Speed Stability ◽  
Aerodynamic Lift

Study on high-speed stability of automobile based on aerodynamic lift feedback

2021 ◽  
Vol 10 (3) ◽  
pp. 293
Author(s):  
Yong Zhang ◽  
Jiaqi Shi ◽  
Ye Xiao ◽  
Qibo Lin ◽  
Fengzhao Mao ◽  
...  
Keyword(s):  
High Speed ◽  
Speed Stability ◽  
Aerodynamic Lift

Numerical Simulation on Aerodynamic Characteristics of Heavy-Duty Commercial Vehicle

2011 ◽  
Vol 346 ◽  
pp. 477-482 ◽  
Author(s):  
Zhe Zhang ◽  
Ying Chao Zhang ◽  
Jie Li ◽  
Jia Wang
Keyword(s):  
Numerical Simulation ◽  
Fuel Economy ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Aerodynamic Characteristics ◽  
National Standards ◽  
Heavy Duty ◽  
Commercial Vehicles ◽  
Automotive Technology ◽  
New Research

With the development of automotive technology and high-speed highway construction, the speed of the vehicles increase which cause the significant increase in the aerodynamic drag when road vehicles are moving. Thereby the power of the vehicles, fuel economy, operational stability and other properties are affected very seriously. Heavy-duty commercial vehicles as the most efficient way to transport goods on the highway are widely used, and the speed of the vehicles increases faster. Especially the demands for heavy-duty commercial vehicles are increasing in recent years. Reducing the aerodynamic drag by the analysis of external aerodynamic characteristics, improving the fuel economy and reducing energy consumption have become new research topics of heavy-duty commercial vehicles. To make the heavy-duty commercial vehicles meet the national standards of energy saving, a simplified heavy-duty commercial truck model was built in this paper. The numerical simulation of the vehicle was completed based on the theory of the aerodynamics. The aerodynamic characteristics were analyzed, according to the graphs of the pressure distribution, velocity distribution and flow visualization. To improve the aerodynamic characteristics of heavy-duty commercial vehicles, the main drag reduction measures are reducing the vortex of the cab and the container, the end of the container and the bottom of the container.

Influence of a high-speed train passing through a tunnel on pantograph aerodynamics and pantograph–catenary interaction

2016 ◽  
Vol 231 (2) ◽  
pp. 198-210 ◽  
Author(s):  
Ruiping Li ◽  
Weihua Zhang ◽  
Zhou Ning ◽  
Binbin Liu ◽  
Dong Zou ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Contact Forces ◽  
Blockage Ratio ◽  
High Speed Train ◽  
Aerodynamic Forces ◽  
Current Collection ◽  
Uplift Forces

Aerodynamics of trains running inside tunnels change more significantly in comparison with open air scenarios. It has been confirmed that the lateral vibration as well as the aerodynamic drag of the trains is increased and the micro-pressure wave is produced at the tunnel exit when the trains are passing through tunnels. The aim of this article is to explore the impact of a high-speed train passing through a tunnel on the pantograph aerodynamics and the dynamic behavior of the pantograph–catenary interaction. The aerodynamic forces acting on the pantograph are investigated thoroughly by extensive numerical simulations as well as systematic field tests. To investigate the effects of the aerodynamic forces of pantograph on the quality of current collection, the numerical simulations of the pantograph–catenary dynamic interaction are conducted with our proposed model, taking into consideration the action of the aerodynamic uplift forces obtained by the numerical simulations on the pantograph. Then, a series of numerical simulations are also carried out to analyze the effects of the train speed and the blockage ratio on the aerodynamic uplift forces of the pantograph, on the contact forces, as well as on the displacement of the contact wire, while the train is passing through a tunnel. The results reveal that compared with the open air scenarios, the aerodynamic drag and uplift forces of the pantograph, the mean value of the contact force and the displacement level of the registration arm can considerably increase as the train runs inside a tunnel. Moreover, the statistical values of the contact forces and the displacement level of the contact wire become larger while the train is passing through the tunnel at different speeds. On the other hand, the quality of current collection decreases with the increasing of the blockage ratio.

A Study of caravan unsteady aerodynamics

2003 ◽  
Vol 217 (7) ◽  
pp. 551-560 ◽  
Author(s):  
J Darling ◽  
P M Staden
Keyword(s):  
High Speed ◽  
Unsteady Aerodynamics ◽  
Aerodynamic Forces ◽  
Side Force ◽  
Aerodynamic Damping ◽  
Novel Technique ◽  
Handling Characteristics ◽  
Aerodynamic Properties ◽  
Scale Models ◽  
Speed Stability

The high speed stability and handling characteristics of car-trailer combinations are affected by both road and aerodynamic forces. While the tyre-to-road interaction is well understood the action of gusts, passing large vehicles and even small steering inputs will disturb the symmetry of flow and generate aerodynamic forces and moments which are suffcient to affect the handling of the system. Although accidents caused by high speed instability are relatively uncommon a better understanding of these aerodynamic effects will improve safety. In this paper a series of wind tunnel investigations using scale models are presented. Steady state investigations were used to measure the aerodynamic properties of the car-caravan pair while a novel technique was developed to measure the aerodynamic damping derivatives in yaw and side force for a caravan model. These damping derivatives were shown to be destabilizing in most cases of sideslip and stabilizing in yaw although it was demonstrated that high damping derivatives were attained at certain frequencies of excitation.

Design and Aerodynamic Assessment of Diffuser with Longitudinal Separators for Underbody of Sedan

2012 ◽  
Vol 215-216 ◽  
pp. 1033-1037 ◽  
Author(s):  
Xing Jun Hu ◽  
Rui Zhang ◽  
Jian Ye ◽  
Xu Yan ◽  
Zhi Ming Zhao
Keyword(s):  
Relative Position ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Lift Coefficient ◽  
Great Influence ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Coefficient ◽  
Aerodynamic Drag Coefficient ◽  
Diffuser Angle ◽  
High Speed Vehicle

The aerodynamic characteristics have a great influence on the steering stability and the fuel economics of a high speed vehicle. The diffuser located at the aft part of a car underbody is one of the most important aerodynamic add-on devices. The parameters of the diffuser, including the diffuser angle, the number and the relative position of longitudinal separator (LS), the shape of the end plate and etc, will affect the underbody flow and the wake. Here, diffuser with longitudinal separator of different number and relative position was investigated. Numerical simulation was used to study the aerodynamic characteristics of a simplified sedan with different diffuser of longitudinal separator. The study found aerodynamic coefficient of the car changes little when we change the relative position of diffuser's longitudinal separator. Besides, we also found that increasing the number of the diffuser's longitudinal separator will increase the vehicle's aerodynamic drag coefficient and reduce the vehicle's lift coefficient.

scholarly journals CFD Simulation of a Hyperloop Capsule Inside a Low-Pressure Environment Using an Aerodynamic Compressor as Propulsion and Drag Reduction Method

2021 ◽  
Vol 11 (9) ◽  
pp. 3934
Author(s):  
Federico Lluesma-Rodríguez ◽  
Temoatzin González ◽  
Sergio Hoyas
Keyword(s):  
Shock Waves ◽  
Power Consumption ◽  
High Speed ◽  
Cfd Simulation ◽  
Aerodynamic Drag ◽  
Flow Behavior ◽  
Critical Conditions ◽  
Vehicle Speed ◽  
Blockage Ratio ◽  
The Cost

One of the most restrictive conditions in ground transportation at high speeds is aerodynamic drag. This is even more problematic when running inside a tunnel, where compressible phenomena such as wave propagation, shock waves, or flow blocking can happen. Considering Evacuated-Tube Trains (ETTs) or hyperloops, these effects appear during the whole route, as they always operate in a closed environment. Then, one of the concerns is the size of the tunnel, as it directly affects the cost of the infrastructure. When the tube size decreases with a constant section of the vehicle, the power consumption increases exponentially, as the Kantrowitz limit is surpassed. This can be mitigated when adding a compressor to the vehicle as a means of propulsion. The turbomachinery increases the pressure of part of the air faced by the vehicle, thus delaying the critical conditions on surrounding flow. With tunnels using a blockage ratio of 0.5 or higher, the reported reduction in the power consumption is 70%. Additionally, the induced pressure in front of the capsule became a negligible effect. The analysis of the flow shows that the compressor can remove the shock waves downstream and thus allows operation above the Kantrowitz limit. Actually, for a vehicle speed of 700 km/h, the case without a compressor reaches critical conditions at a blockage ratio of 0.18, which is a tunnel even smaller than those used for High-Speed Rails (0.23). When aerodynamic propulsion is used, sonic Mach numbers are reached above a blockage ratio of 0.5. A direct effect is that cases with turbomachinery can operate in tunnels with blockage ratios even 2.8 times higher than the non-compressor cases, enabling a considerable reduction in the size of the tunnel without affecting the performance. This work, after conducting bibliographic research, presents the geometry, mesh, and setup. Later, results for the flow without compressor are shown. Finally, it is discussed how the addition of the compressor improves the flow behavior and power consumption of the case.

On the correlation between aerodynamic drag and wake flow for a generic high-speed train

2021 ◽  
Vol 215 ◽  
pp. 104698
Author(s):  
Xiao-Bai Li ◽  
Xi-Feng Liang ◽  
Zhe Wang ◽  
Xiao-Hui Xiong ◽  
Guang Chen ◽  
...  
Keyword(s):  
High Speed ◽  
Aerodynamic Drag ◽  
Wake Flow ◽  
High Speed Train
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