垂直冲击射流脉动壁压深化研究

通过实验对垂直冲击射流的脉动壁压统计特性进行了研究,给出了脉动壁压强度沿纵向的变化规律及其拟合公式,谱密度函数具有低频窄带特性,具体情况与距冲击点的距离和水深有关.并对实验测得的脉动壁压场进行了正交分解与低阶近似的研究.计算结果表明,冲击射流所形成的脉动壁压场可用正交分解进行描述,其特征谱函数随阶数的增加而迅速衰减,对谱密度函数进行低阶近似也非常有效.

Investigation on wall-pressure fluctuation of vertically impinging jet

The statistical properties of wall-pressure fluctuation by vertically impinging jet was investigated experimentally. The stream-wise distribution of wall-pressure fluctuation intensity was discussed. The spectral density functions are low frequency and narrow band, and they are different with the changes of length from impinging point and the depth of water. The method of proper orthogonal decomposition and low order approximation was also used to study the wall-pressure fluctuation field obtained from experiment. The results show that the eigen spectral functions declined with the increasing of order rapidly. The reconstruction of spectral density function shows that low order approximation is very efficient.