减阻沟槽表面近壁湍流相干运动的实验研究

Experiment on coherent motions in the turbulent near-wall region over a drag-reducing grooved surface

以光滑平板及间隔V型减阻沟槽面为研究对象,利用二维激光多普勒测速系统(laser doppler velocimetry,LDV),获得零压力梯度时光滑平板及沟槽板上部区域湍流边界层流场的流向和壁法向的湍流脉动分量.考察了沟槽对速度脉动的二阶及三阶相关统计参数的影响,并将这些相关量的变化情况与边界层中的相干运动相结合,由此来探讨沟槽面与湍流边界层之间的相互作用规律.

Measureraents of flow field by means of a two-compouent LDV system have been carried out in turbulent boundary layers over a smooth surface and a drag reducing grooved surface with a zero pressure gradient. Variations of the second- and third-order moments of velocity fluctuations are investigated to give thorough information on coherent motions in the turbulent near-wall region over both surfaces.