边界层内低阶结构函数标度律的实验研究

利用PIV系统对平板湍流边界层在Reθ=2?167下流向(u′)和法向脉动速度(v′)进行了测量,研究结果显示,当脉动增量的结构函数的阶数为 正分数时,实验所得的标度指数和K41及SL标度指数较为接近;当结构函数的阶数为分数且由0趋向于-1时,实验的标度指数明显偏离K41和SL标度指数,出现奇异标度律。这也说明了用低阶结构函数的标度指 数也能说明标度律的奇异性及边界层内存在间歇性。

Experimental research for scaling of low-order structure function in the boundary layer

Scaling laws in the wall region of a turbulent flow were addressed by analyzing the moments of velocity increments obtained by the particle image velocimetry (PIV) system in the boundary layer of a flat plate. The moments of increments of upstream velocity (u′) and longitudinal velocity (v′) were measured at　Reθ=2?167 in different wall distances and the scaling of non integer moments of order between +2 and -1 were discussed. The difference of scaling exponents of low order structure functions between the experimental data and Kolmogorov’s, SL’s (She ＆ Leveque) prediction increases as the moment order decreases toward 1, which shows that the anomaly is manifested in low order moments as well.