壁面粗糙度突变对湍流边界层的影响

Effect of Turbulent Boundary Layer to a Small Step Change in Wall Roughness

本文探讨了湍流在流过不同粗糙度的壁面时粗糙度突变对突变点下游流动的影响.假定粗糙度突变引起的扰动为小扰动,流动物理量的扰动值满足自相似分布,本文分析得到了描述突变点下游流动特性的长度尺度、速度剖面、时均流速及摩阻流速的表达式,并通过实验对理论分析的结果进行了验证.

In this paper the effect of a small step change in wall roughness on turbulent boundary layer is studied. Under the assumptions that the step change only causes small disturbance to the flow field and the per-turbed quantities possess self-similarity distribution, the analysis results in the formulae of the length scale, ve-locity profiles, time-averaged velocity and friction speed characterizing the flow downstream the step change, which are verified with experimental data.