Analysis Of Vehicle Aerodynamics Performance Base On Turbulent Model

By2010, China has become the world’s biggest car producer and consumer, yetstill can’t be named the auto power. Automobile research and development ability isstill weak, and in the automotive aerodynamic characteristic, there is a long distanceto the foreign high-end research field.Currently, computational fluid dynamic (CFD), has increasingly become the maintool and method of car aerodynamics, being applied more and more to the car’sdevelopment process. Based on the turbulence models, many problems had beensolved.In this paper, turbulence models’ problems encountered in the process as astarting point, made a series of solutions and measures, and turbulence modelsthrough the actual study to validate its effectiveness, so as to provide aerodynamicresearch related to scientific theory.The paper describes the commercial CFD software Fluent briefly. Thenfrequently-used grid types are compared and the most suitable mesh type forautomobile external flow field is established. Based on the MIRA model, the paperestablishes the calculation mesh model using the CFD software. In the solving process,using the turbulence models of Standard k ε, RNG, Realizable and SST, the paperanalyzes the external flow field under the same mesh and boundary condition. Besides,the paper mainly focuses on the lift feature, drag feature, convergence property andflow field characteristic of the four turbulence models. By analyzing the calculationresult of the four turbulence models, the suggestion of choosing different turbulencemodels according to difference applications is put forward.For the application of the automobile outflow field analysis, the paper chooses thestandard k εand Realizable turbulence models as optimized objects throughcomparing the four turbulence models. The paper studies the influence of parametersin the model and gives targeted improvement optimization. To further improve thecalculation accuracy and meet the analysis requirements of flow field, the paperimproves the turbulence models and provides support for future car flow field analysis.Finally, based on turbulence model, the paper puts forward car aerodynamic liftfitting formula and gives a new idea to CFD simulation.