双股射流壁面脉动压强与近壁紊动流速相关与频谱特性

Correlative Characteristics between Wall Fluctuating Pressure and Fluctuating Velocity of Two Impinging Jets

本文用多通道动态压力检测系统和二维激光测速仪对在单股和双股射流作用下，水垫塘底板脉动压强与近壁脉动流速的相关、功率谱和紊动比尺进行了测试研究。实测表明，双股射流形成的动水垫在塘底水平方向的脉动使得双股射流在第二冲击点下游的脉动量特性与单股射流不同：前者的水平脉动速度与脉动压强的互相关系数较后者明显增大，且水平脉动速度和脉动压强的功率谱具有大致相同的优势频率。单股和双股射流塘底脉动压强系数与近壁紊流强度的关系可用对数曲线表述。

The correlation,the spectrum and the turbulent scale of wall fluctuating pressure and fluctuating velocity,under the action of single and twin impinging jets,are studed in the paper by using 2-D LDA and the multiple points dynamic pressure scanning system.It is found that the fluctuating characteristics of twin jets are different from single jet because of the affection of the 'moving water cushion 'produced by twin jets The cross correlation between horizontal fluctuating velocity and fluctuating pressure of twin jets is begger than that of single jet,and the spectrum of horizontal fluctuating velocity cud fluctuating pressure obviously has dominant frequency.The relationship of the fluctuating pressure coefficient on wall and the turbulent intensity near the wall can be described with logarithmic curve.