y+值对翼型气动参数计算精度的影响研究

基于RAE 2822翼型,为了研究粘性底层无量纲参数y+对翼型气动参数计算精度的影响,采用ANSYS ICEM剖分的计算域网格和三维N-S控制方程的有限体积法离散格式,选取SST湍流模型,在不同的y+值下借助ANSYS CFX模块数值计算了该翼型的气动参数,分析了相对误差,绘制了压力系数分布云图。结果表明:过大的y+值导致误差增大;在y+的理论值11.63附近,计算精度变化较小;较小的y+可使精度进一步提高,但过小的y+并不能得到过高的计算精度。y+值对翼型边界不同区域的计算精度影响有所不同,翼型气动参数数值计算时推荐y+取2-4。

The Study of Effect of y+ on Precision of Pneumatic Parameters of Foil

Based on foil RAE 2822, in order to research the effect of y+ of non-dimensional quantity parameters on computing precision of pneumatic parameters of foil, the computational grids created by ANSYS ICEM and the disperse format of N-S control equations with the method of finite volume method are employed, SST turbulence model is selected, pneumatic parameters of foil are numerically simulated. The relative error is analyzed, and the contour of pressure coefficient is drawn recurring to ANSYS CFX module under different y+. The results show that too large y+ leads to the increase of error, the computing precision is less change nearby the theoretic value 11.63 of y+ and lesser y+ may make the precision further improved, but higher precision couldn''t be with too small y+. The impacts of y+ on the computing precision are various in different regions of foil boundary, and y+ selected between 2 to 4 is recommended when pneumatic parameters of foil are simulated.