Comparative Study on External Flow Simulation of Passenger Car with Complex Underbody and Flat Underbody

2013 ◽  
Vol 380-384 ◽  
pp. 69-72 ◽  
Author(s):  
Xu Yan ◽  
Xin Qiao ◽  
Zhi Ming Zhao ◽  
Jian Ye ◽  
Lei Liao ◽  
...  
Keyword(s):  
Flow Field ◽  
Aerodynamic Drag ◽  
Flow Simulation ◽  
Aerodynamic Characteristics ◽  
External Flow ◽  
Field Structure ◽  
Passenger Car ◽  
Car Model ◽  
Cfd Method ◽  
Aerodynamic Drag Reduction

In this paper, the external flow simulation has been carried out on a simplified passenger car model with two schemes adopted: a smoothed complex underbody and a flat underbody. The aerodynamic characteristics and the flow field structure of the passenger car model were obtained with CFD method, and the drag coefficients of the smoothed complex underbody and the flat underbody are respectively 0.275 and 0.251. According to the simulation, flow separation and energy loss of fluid was caused by protuberances on the complex underbody. As there are many differences between the aerodynamic characteristics of the smoothed underbody and the flat one, its suggested to use a smoothed complex underbody not a flat underbody in the studying of aerodynamic drag reduction of a passenger car.

Application of RNG k-ε Turbulence Model on Numerical Simulation in Vehicle External Flow Field

2012 ◽  
Vol 170-173 ◽  
pp. 3324-3328 ◽  
Author(s):  
Jing Yu Wang ◽  
Xing Jun Hu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Turbulence Model ◽  
Aerodynamic Drag ◽  
Wind Tunnel Test ◽  
Turbulence Models ◽  
Aerodynamic Characteristics ◽  
External Flow ◽  
Car Model ◽  
Drag And Lift

The two turbulence models were used to numerically simulate the external flow field around the Ahmed standard car model, and the aerodynamic drag and lift coefficients and aerodynamic characteristics around model were obtained. By comparison between the simulation results and the corresponding wind tunnel test data, the differences of two turbulence models were analyzed. The results indicated the simulation result of RNG k-εturbulence model is more precision, and it is more suitable on numerical simulation in vehicle external flow field. The conclusions provide reference for how to select turbulence model.

scholarly journals Numerical Simulation and Analysis of External Flow Field of the Van

2019 ◽  
Vol 293 ◽  
pp. 01001
Author(s):  
Kan Zhou ◽  
Ge Huang ◽  
Bin Liu ◽  
Qi Hu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Vortex Motion ◽  
Aerodynamic Characteristics ◽  
External Flow ◽  
Calculation Results

This paper uses CFD preprocessing software to build Van model and gridding it, then CFD software is used to simulation the outflow field of Van model, from which the distribution of pressure and velocity is obtained and the outflow field is analyzed. The calculation results indeed reflect the aerodynamic characteristics of the external flow field of the van, and the flow movement on the van surface is better simulated. In addition, the positions where the vortex motion is relatively severe are also found

Actively translating a rear diffuser device for the aerodynamic drag reduction of a passenger car

2012 ◽  
Vol 13 (4) ◽  
pp. 583-592 ◽  
Author(s):  
S. O. Kang ◽  
S. O. Jun ◽  
H. I. Park ◽  
K. S. Song ◽  
J. D. Kee ◽  
...  
Keyword(s):  
Drag Reduction ◽  
Aerodynamic Drag ◽  
Passenger Car ◽  
Aerodynamic Drag Reduction

Numerical Optimization Research on Rear Characteristic Angles Based on MIRA Model for Aerodynamic Drag Reduction

2013 ◽  
Vol 774-776 ◽  
pp. 428-432
Author(s):  
Qian Qian Du ◽  
Xing Jun Hu ◽  
Qi Fei Li ◽  
Yu Kun Liu ◽  
Bo Yang
Keyword(s):  
Inclination Angle ◽  
Numerical Optimization ◽  
Cfd Simulation ◽  
Aerodynamic Drag ◽  
Optimization Method ◽  
Aerodynamic Design ◽  
Rear Window ◽  
Passenger Car ◽  
Two Parameters ◽  
Aerodynamic Drag Reduction

The rear characteristic angles of the passenger car in this study were defined as the inclination angle of rear window and the bottom inclination angle of aft based on the MIRA model. The numerical optimization method was used to analyze the influence of combined variation of two angles on the external flow field and the CD of the passenger car, in which we combined genetic algorithm with the CFD simulation to reduce aerodynamic drag by seeking the relatively optimal combination of two parameters above. The study reveals that when the combination of the inclination angle of rear window and bottom inclination angle of aft is 25oand 0.067o, the total pressure and streamline distribution in the flow fields of the MIRA model are improved greatly and the CD is reduced compared with the worst combination. This conclusion will have profound guiding significance in the aerodynamic design of the rear styling and shape of a car.

Aerodynamic Simulation of Road Vehicle in Steady Crosswind

2013 ◽  
Vol 376 ◽  
pp. 341-344
Author(s):  
Shan Ling Han ◽  
Ru Xing Yu ◽  
Yu Yue Wang ◽  
Gui Shen Wang
Keyword(s):  
Flow Field ◽  
Wind Direction ◽  
Motor Vehicle ◽  
Aerodynamic Force ◽  
Flow Characteristics ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
External Flow ◽  
Slant Angle ◽  
Ahmed Body

Because crosswind affects drivers to control their vehicles safely, the research on flow characteristics in automotive crosswind has a great significance to improve the crosswind stability of the vehicle. By the steady state numerical simulation method, the aerodynamic characteristics of external flow field of Ahmed body in crosswind was investigated. The Ahmed body with 25° slant angle is built in UG NX. The external flow field of the Ahmed body in the wind direction of 0°, 15º, 30° angle is simulated in XFlow software. According to the map of the pressure and velocity distribution, the flow field both before and after, as well as left and right has significant change as the wind direction angle increased, and the trail turbulence intensity also changes. The changes of aerodynamic force and moment affect the driving stability of a motor vehicle.

Investigation of the Cooling and Underbody Flow Field on a Detailed Scale Model Passenger Car: Part 2—Effect of Ground Simulation

2009 ◽  
Author(s):  
Christoffer Landstro¨m ◽  
Lasse Christoffersen ◽  
Lennart Lo¨fdahl
Keyword(s):  
Reynolds Number ◽  
Flow Field ◽  
Aerodynamic Drag ◽  
Scale Model ◽  
Experimental Investigations ◽  
Passenger Cars ◽  
Local Flow ◽  
Passenger Car ◽  
Reynolds Number Effects ◽  
Cooling Air

Future demands on passenger cars consist to a large extend of making them more energy efficient. Reducing the driving resistance by reducing the aerodynamic drag will be one important part in reducing fuel consumption. In most cases during passenger car development, early experimental investigations are performed in scale model wind tunnels. Considering that such models inevitably suffer from Reynolds number effects it is important to understand how this affects the test results. Investigations of the aerodynamics of a detailed scale model Volvo S60 have been performed in the aerodynamic wind tunnel at Chalmers University of Technology. The investigation aimed at increasing the understanding of how the flow field in scale model testing is affected by ground simulation and different cooling air flow configurations at different Reynolds numbers. A full width moving ground system was used in the experiments. Pressure taps were distributed between the cooling air inlets, the underbody and the vehicle base. An internal six component balance was used to measure global forces and moments. By combining the results from the measurements it was possible to increase the understanding of some of the local flow features. Results showed significant Reynolds number effects both with stationary ground as well as moving ground and rotating wheels. Global aerodynamic drag as well as front and rear axle lift was found to be affected.

Study of Truck’s Aerodynamic Drag Reduction Based on Jet

2014 ◽  
Vol 635-637 ◽  
pp. 316-319
Author(s):  
Peng Guo ◽  
Jun Yuan Zhang ◽  
Qi Fei Li ◽  
Xing Jun Hu
Keyword(s):  
Numerical Simulation ◽  
Comparative Analysis ◽  
Flow Field ◽  
Drag Reduction ◽  
Pressure Distribution ◽  
Aerodynamic Drag ◽  
Outer Flow ◽  
Air Movement ◽  
Maximum Drag Reduction ◽  
Aerodynamic Drag Reduction

Multiple schemes are adapted on truck's outer flow field based on numerical simulation. Comparative analysis with the state of air flow, the pressure distribution, the air movement between the cab and cargo is pursued, then obtain the effect of jet flow velocity to the truck Cd. With the increasing of the jet velocity, Cd increases first and then decreases. The maximum drag reduction can reaches 7.38%.

Vehicle Aerodynamic Drag Reduction Using Air Jet System

2017 ◽  
Author(s):  
SangWook Lee
Keyword(s):  
Drag Reduction ◽  
Aerodynamic Drag ◽  
State Of The Art ◽  
Sensitivity Study ◽  
Air Jet ◽  
Aerodynamic Drag Coefficient ◽  
Parametric Studies ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Aerodynamic Drag Reduction

Study on the air jet wheel deflector system using state-of-the-art of Computational Fluid Dynamics (CFD) technique based on an open domain CFD software (OpenFOAM) is performed to reduce vehicle aerodynamic drag. Fabijanic’s simple vehicle model [1] is used for both the mesh sensitivity study and validation of current CFD technique. It was found that CFD method used in this study is reliable tool for the forecasting of the aerodynamic drag coefficient. Parametric studies were conducted to investigate aerodynamic effects of the conventional wheel deflector and air jet wheel deflector system. For the conventional wheel deflector, 3.6% of drag reduction was achieved with a non-dimensional deflector height of 1/6, but the drag force tends to increase as the non-dimensional height increased. On the other hand, it was shown that air jet wheel deflector system can reduce vehicle aerodynamic drag up to 7.5% at the non-dimensional air jet velocity of 1.0. Therefore it would be concluded that air jet wheel deflector is a useful device to reduce aerodynamic drag of automobile.

scholarly journals Wake Flow Investigation on Notchback MIRA Model by PIV Experiments

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4568
Author(s):  
Yingchao Zhang ◽  
Jinji Li ◽  
Zijie Wang ◽  
Qiliang Wang ◽  
Hongyu Gong ◽  
...  
Keyword(s):  
Flow Field ◽  
Aerodynamic Drag ◽  
Three Dimensional ◽  
Field Structure ◽  
Wake Flow ◽  
Scale Model ◽  
Flow Mechanism ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Piv Method

To deepen our understanding of the flow field and flow mechanism of a car-like model, in this paper, an experimental investigation of the flow field of MIRA notchback 1/8 scale model is carried out using Particle Image Velocimetry (PIV) method. The tests are conducted in an open circuit wind tunnel at a Reynolds number of . In order to obtain the detailed flow field structure of the notchback model, the PIV method was used to capture the flow field images from three orthogonal directions. By studying the vorticity and velocity vector figures of both the time-averaged and instantaneous states, a three-dimensional flow field schematic of the notchback model is summarized, and the formation mechanism and development process of the vortices are analyzed. This study not only provides an intuitive display of the three-dimensional flow field structure of the MIRA notchback model but, more importantly, it provides a reference for the development of automobile aerodynamic drag reduction by analyzing the flow mechanism, which is beneficial to energy conservation.

A Review of Commercial Vehicle Aerodynamic Drag Reduction Techniques

1985 ◽  
Vol 199 (3) ◽  
pp. 215-220 ◽  
Author(s):  
K P Garry
Keyword(s):  
Aerodynamic Drag ◽  
Fuel Efficiency ◽  
Relative Effectiveness ◽  
Aerodynamic Characteristics ◽  
Performance Assessments ◽  
Commercial Vehicles ◽  
Reduction Techniques ◽  
Legal Constraints ◽  
And Performance ◽  
Aerodynamic Drag Reduction

The aerodynamic characteristics of commercial vehicles have been of interest to researchers for many years, primarily with a view to reducing drag and consequently improving fuel efficiency. Despite developments in the design of low drag vehicles proprietary devices in various forms remain the most effective method of reducing drag on the majority of vehicles in current use. The relative effectiveness of these devices is discussed in relation to the variety of vehicle geometries to which they are fitted and performance assessments are made, particularly with reference to the need for crosswind efficiency. A general summary of potential aerodynamic developments is given, emphasizing the concept of matching the flowfield of cab and container to obtain optimum interference. The effectiveness of cab–container gap seals and trailer side skirts, both intended to reduce drag under crosswind conditions, is also discussed. All such developments are taken in the context of existing commercial and legal constraints likely to influence their impact on the next generation of commercial vehicles.

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