二维单一粗糙元对边界层转捩影响的实验

在风洞中对水平光滑平板以及加有粗糙元平板的边界层转捩进行了测量与研究，比较了不同情况下平板边界层内由振动梁激励生成的T-S波沿流向和法向强度的分布规律，得到了相应的振型、增长曲线以及中性曲线。实验中发现与光滑平板边界层的下端开放式的拇指型中性曲线相比较，有粗糙元平板的中性曲线为封闭式的环形曲线，随着粗糙元高度的进一步增加中性曲线收缩为更小的闭合环。

An Experimental Investigation on the Effect of Single Two-Dimensional Roughness Elements on Boundary-Layer Transition

An experimental investigation on the transition in the boundary-layer of horizontal plane with and without single two-dimensional roughness elements has been carried out in the wind tunnel. The distribution in normal and stream-wise directions of intensity of T-S wave excited by vibrating beam was measured in every condition. Neutral curves were obtained by measuring the growth of the T-S wave at the normal critical location along the stream-wise direction. Comparing with the neutral cave on the smooth plane that was thumb-like and opened at the bottom, the neutral caves on the plane with single roughness elements were closed circles. With the growing of roughness element's height, the closed circle became smaller.