Drag reduction in a turbulent boundary layer on a flexible sheet undergoing a spanwise traveling wave motion
Drag reduction in a turbulent boundary layer on a flexible sheet undergoing a spanwise traveling wave motion
复制标题
DOI：
10.1080/14685240600647064
复制
发表时间：
2006-01
影响因子：
1.9
通讯作者：
M. Itoh;Shinji Tamano;K. Yokota;Shinya Taniguchi
中科院分区：
文献类型：
--
作者：
M. Itoh;Shinji Tamano;K. Yokota;Shinya Taniguchi
在低雷诺数条件下，利用热线风速仪和激光位移传感器研究了展向行波运动对柔性板上零压力梯度湍流边界层的影响。结果发现，对数律区域的平均速度的柔性片材上的刚性壁相比，略窄。柔性板上的流向速度波动的能谱进行展向行波运动较小的频率区域，对应于在典型的壁湍流的爆发频率。这表明柔性板附近的破裂事件直接受到表面波运动的影响。结果表明，可以通过展向行波运动获得高达7.5%的减阻，通过动量厚度的增长率估计摩擦系数。
The effect of a spanwise traveling-wave motion on a zero-pressure-gradient turbulent boundary layer over a flexible sheet was investigated at low Reynolds numbers using a single hot-wire anemometer for turbulence statistics and two laser displacement sensors for displacements of the flexible sheet. It was found that the log-law region of the mean velocity on the flexible sheet was slightly narrower compared with a rigid wall. The energy spectra of streamwise velocity fluctuations on the flexible sheet undergoing the spanwise traveling-wave motion were smaller in a region of frequency which corresponded to the bursting frequency in the canonical wall turbulence. This indicates that the bursting event near the flexible sheet was directly affected by the surface wave motion. It was revealed that a drag reduction of up to 7.5% could be obtained by the spanwise traveling-wave motion, estimating the friction coefficients through the growth rate of the momentum thickness.