Experimental Study on Control of the Wall Turbulence with Spanwise Discontinuity of Surface Roughness

实验研究表明，表面粗糙度展向不连续引起的纵向涡的存在及其产生机理。纵向涡沿表面粗糙度的不连续面产生，并产生二次电流。对纵向涡度输运方程中产生项的计算表明，湍流分布有助于涡度的产生。这一发现可应用于无突出高度的涡发生器。

An experimental study shows existence of longitudinal vortex by spanwise discontinuity of surface roughness and its producing mechanisms. The longitudinal vortex is generated along the discontinuity of surface roughness and induces secondary current. Evaluation of production terms in the transport equation of the longitudinal vorticity reveals that turbulence distributions contribute to the vorticity production. This finding could be applied to vortex generator without protrusion height.