TURBULENCE REDUCTION IN A BOUNDARY-LAYER BY A LOCAL SPANWISE OSCILLATING SURFACE
TURBULENCE REDUCTION IN A BOUNDARY-LAYER BY A LOCAL SPANWISE OSCILLATING SURFACE
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DOI：
10.1063/1.868052
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发表时间：
1994-10-01
影响因子：
4.6
通讯作者：
MOREL, R
中科院分区：
文献类型：
--
作者：
LAADHARI, F;SKANDAJI, L;MOREL, R
本文描述了平板上湍流边界层对壁面局部展宽振动响应的实验研究，无因次频率f~+在0.0033~0.0166之间变化。对壁面运动幅度DELTAz+=160进行了研究。湍流强度和雷诺应力的三个分量是频率的递减函数。这种折减几乎影响了位于振荡壁中间的横截面中的整个边界层。在整个y+<；30区域内，平均流向速度Ubar减小。当与y作图时，速度剖面显示出一个明确的对数区域，与未扰动边界层的摩擦速度无量纲化。U和u的加权概率密度函数显示出与振荡流结构变化相关的壁向运动强度的增加。湍流的精细结构也受到展向振荡的影响，这表现在泰勒微尺度的减小上。
This Letter describes an experimental investigation of the response of a turbulent boundary layer on a flat plate to a local spanwise oscillation of the wall, with a nondimensional frequency f+ varying between 0.0033 and 0.0166. The investigation has been carried out for a wall motion amplitude DELTAz+ = 160. The three components of the turbulence intensities and the Reynolds stress prove to be a decreasing function of the frequency. This reduction affects almost the whole boundary layer in a cross section located at the middle of the oscillating wall. The mean streamwise velocity UBAR is reduced throughout the region y+ < 30. The velocity profiles exhibit a well-defined log region when plotted against y, nondimensionalized with the friction velocity of the unperturbed boundary layer. The weighted probability density functions of u and upsilon exhibit an increase in intensities of wallward motion related to changes in the structure of the oscillatory flow. The fine structure of the turbulence is also affected by the spanwise oscillation as shown by the reduction of Taylor's microscale.