Control of the Turbulent Flow over a Two-dimensional Rough Wall with Longitudinal Micro grooves

点击翻译按钮获取中文摘要

The effect of the spanwise three-dimensionality of the rough wall introduced by longitudinal micro-grooves has been investigated on the mean and turbulent quantities for a turbulent boundary layer. The boundary layer development has little effect of the three-dimensionality. For the outer layer, the streamwise mean velocity and turbulent intensity profiles are well agreement with those of the two-dimensional rough wall flow, but near the rough wall these values increase. From the detailed measurement near the rough wall, the streamwise mean velocity and turbulent intensity profiles show a periodicity in the spanwise direction corresponding to the micro-grooves. Behind the micro-groove, the streamwise mean velocity is accelerated and the turbulent intensity is enhanced in comparison with those of the two-dimensional rough wall flow. On the drag acting on the rough wall, the three-dimensionality has little influence. The virtual origin of the height direction estimated by the pressure distribution around a roughness element and the drag shifts downward compared with that of the two-dimensional rough wall flow.