用平均速度剖面法测量湍流边界层壁面摩擦速度的对比研究

基于不同雷诺数平板湍流边界层平均速度剖面,分别采用黏性底层拟合、对数律区拟合以及Spalding公式拟合算法计算了壁面摩擦速度,并对平均速度剖面进行无量纲化。通过比较无量纲化的平均速度剖面与理论规律曲线,验证了三种拟合计算方法的有效性。通过比较三种拟合算法所得的壁面摩擦速度与油膜干涉法直接测得的壁面摩擦速度之间的误差,并分析不同拟合算法误差形成的内在机制,验证了三种拟合算法计算结果的准确性与可靠性。结果表明Spalding拟合算法计算结果的准确性和可靠性都要优于其他两种拟合算法。

Comparative study of turbulent boundary layer wall friction velocity measured by average velocity profile method

Based on average velocity profile of plate turbulent boundary layer with different Reynolds numbers, the wall friction velocity was calculated by using the viscous bottom layer fitting algorithm, the logarithmic law region fitting algorithm and Spalding formula fitting algorithm, respectively, and the average velocity profile was non-dimensionalized. By comparing the dimensionless average velocity profile with the theoretical curve, the validity of above three fitting methods was verified. Then the wall friction velocity error obtained by above three fitting algorithms was compared with that measured directly by oil film interference method, and the internal mechanism of the error formation of different fitting algorithms was analyzed. The accuracy and reliability of above three fitting algorithms were verified. Results show that the accuracy and reliability of Spalding fitting algorithm are better than the other two fitting algorithms.