Laminar streaks with spanwise wall forcing
Laminar streaks with spanwise wall forcing
复制标题
具有展向壁力的层流条纹
DOI：
10.1063/1.3593469
复制
发表时间：
2011
影响因子：
4.6
通讯作者：
P. Ricco
中科院分区：
文献类型：
--
作者：
P. Ricco
本文用数值方法研究了跨向壁面速度的稳定正弦振荡对过渡前Blasius边界层中自由湍流引起的非定常条纹波动的影响。壁面运动产生沿展向边界层，沿展向边界层沿x /6向下游生长，并在较大的下游距离处有渐近解析解。虽然强迫对条纹的初始生长没有影响，但它们的强度最终会根据强迫波长与条纹特征长度尺度之间的相对大小而大幅增加或减少。当条纹展长尺度远大于边界层厚度时，壁面驱动可以增强条纹强度。当沿展向粘性扩散效应起关键作用时，条纹能量反而衰减。在这种情况下，壁面压力波动也可能得到显著抑制。由全谱free产生的k黎巴嫩夫模…
The influence of steady sinusoidal oscillations of spanwise wall velocity on the Klebanoff modes, i.e. unsteady streaky fluctuations induced by free-stream turbulence in the pre-transitional Blasius boundary layer, is investigated numerically. The wall motion induces a spanwise boundary layer which grows downstream as x1/6 and has an asymptotic analytical solution at large downstream distances. While the forcing has no effect on the initial growth of the streaks, their intensity eventually increases or decreases substantially depending on the relative magnitude between the forcing wavelength and the characteristic length scales of the streaks. The wall actuation enhances the streak intensity if the streak spanwise length scale is much larger than the Blasius boundary layer thickness. The streak energy is instead attenuated when the spanwise viscous diffusion effects play a key role. Wall pressure fluctuations may also be significantly damped in this case. The Klebanoff modes generated by full-spectrum fre...