Research On The Turbulence Model Of The Automobile External Flow Field And The Aerodynamic Characteristics Of The New Rhombus Concept Vehicle

The aerodynamic characteristics are very important to the automobile dynamic performances, the fuel consumption, the comfort and the safety. For example, the decrease of the aerodynamic drag force coefficient which is proportional to the square of the velocity can greatly reduce the fuel consumption especially at the high speed. The vehicle stability in the lateral wind is also a crucial guideline for the vehicle safety performance especially at the high speed.Because the separated flow and turbulence behind the automobile have great effect on the automobile aerodynamics, the precise turbulence model for the accurate simulation of the automobile aerodynamic characteristics has become the most difficult problem and keystone in the simulation. The turbulence models applied in the traditional simulation of the automobile external flow field are commonly based on the "general" condition. In fact, the automobile external flow field has some different aspects from the "general" condition. So, a more suitable turbulence model should be developed based on the property of the automobile external flow field.From the theory aspect, a new turbulence model has been developed based on RSM equations combining the analysis of near-wall asymptotic behavior in the automobile external flow field with the tensor theory and low-Re modification.From the calculation, the aerodynamics simulations of the new concept vehicle and the traditional car get the drag and lift coefficients and other results based on the newly developed turbulence model.From the experiment, the aerodynamics of the new concept vehicle has been investigated by the PIV and the wind-tunnel experiment which verify the simulation results.In particular, the following work including the innovation has been completed:1. Summarize the domestic and international research and development status of the automobile external flow field numerical simulation. For the first time, a new LRNLEVM (low-Re Nonlinear Eddy Viscosity Model) is brought forward based on the property of the automobile external flow field. In the modeling process, the EASM (Explicit Algebraic Stress Model) including the detailed mechanism of the...