基本湍流模型在轿车底部流场的仿真分析

Simulation and Analysis of Basic Turbulence Models Applied to Under-vehicle Flow

利用CFX10.0针对轿车车身底部流场进行仿真,主要是以稳态的控制体积为研究对象,Navier-Stokes Equations为数学工具,采用标准κ-ε和RNGκ-ε湍流模型对移动壁面边界的气动特性做了详细解释。同时,也较好地对底部流场的物理机理及车身的气动特性进行了深入的分析。结果表明:移动的壁面可以减弱附面层对车身气动特性的影响,该模拟结果与轿车模型在风洞中的试验结果比较一致。对轿车车身局部流场的分析有利于改善高速运动轿车的气动布局和提高轿车的气动特性。

This paper introduces the simulation of the under - vehicle air flow with CFX 10.0 software, in which the steady control volume is studied by using the mathematical tool Navier - Stokes equations. The standard κε and RNGκ-ε turbulence models have been adopted to simulate the under - vehicle air flow and the aerodynamic behaviors of moving wall boundary are explained profoundly. Meantime the physical mechanism of this under - vehicle airflow field and the aerodynamic performances of car＇s body are deeply analyzed. The results give conclusions that the moving wall can reduce the influences of boundary layer on aerodynamic performances of car＇s body and the results of simulation are comparatively coincident with the experimental results of car model in the wind tunnel. The analysis of local air flow of car＇s body can improve the aerodynamic distribution and upgrade its aerodynamic behaviors.