Y+值对地面交通工具气动阻力计算精度影响的研究  

Research of Effect of Y + on Precision of Aerodynamic Drag of Ground Transportation

作　　者：赖晨光[1] 任浡麒 满超[1] 

机构地区：[1]重庆理工大学车辆工程学院,重庆400054

出　　处：《重庆理工大学学报（自然科学）》2015年第10期7-11,共5页Journal of Chongqing University of Technology：Natural Science

基　　金：国家自然科学基金资助项目(51305477)

摘　　要：为研究无量纲长度Y+变化对汽车阻力系数的影响,以Mira模型为基础,采用有限体积法,运用ANSYS ICEM CFD模块对模型进行网格划分,并使用FLUENT进行计算。在保证网格数量相近、质量相等的前提下得到不同Y+值下汽车所对应的阻力系数,并与试验精确值进行对比,分析相对误差。对比分析了与风洞试验值相近的案例和相对误差较大的案例所对应的汽车对称平面处的压力云图。结果表明:Y+在理论值附近时计算精度最高,过大的Y+值会明显降低计算精度,而过小的Y+值并不能得到足够的计算精度。Finite volume method,based on MIRA model,was used to research the influence on the automobile drag coefficient because of the change of a dimensionless parameter Y ＋. ANSYS ICEM CFD was used to build mesh and FLUENT was used to do calculation. As a precondition,making sure the numbers of mesh similar and the quality of mesh same,different automobile drag coefficients were worked out following Y ＋ changing and the relative error between calculated values and experiment values. Two different pressure contours located in the middle plane of the MIRA car model were compared and analyzed with the result of one with small relative error to the accurate value and another with larger. The conclusion shows that the computing result has the smallest error when it is close to the experiment value,and larger Y ＋ or less Y ＋ all does not have enough computing accuracy. Too large Y ＋ leads to the decrease of the accuracy while if the Y ＋ is too small,it cannot get enough calculation accuracy.

关 键 词：Y+值 CFD 空气动力学 数值模拟 误差分析 

分 类 号：U467[机械工程—车辆工程]