基于湍流边界层时均速度分布的脊状表面减阻规律研究

Research about the characteristic of drag reduction over riblets surface based on average velocity profile in the turbulent boundary layer

通过对试验测得的脊状表面湍流边界层时均速度分布的分析,获得了脊状表面的减阻范围和基本规律.脊状表面理论零点及壁面摩擦速度的计算采用基于湍流边界层Spalding壁面律公式的最小二乘拟合方法;模型板摩擦阻力计算采用基于边界层动量积分方程的方法.研究表明:脊状结构使得湍流边界层粘性底层增厚,近壁面法向速度梯度降低,过渡层与对数律区上移;V型脊状结构的无量纲宽度s+介于6至18时具有减阻效果;当s+≈12时,减阻量最大,最大值约7.7%.

Through thorough analysis about the characteristic of average velocity profile in the turbulent boundary layer over riblets surface that was measured by a hot wire anemometry in a miniature special wind tunnel,the drag reduction ranges and rules were acquired.In the calculation of virtual origin and wall friction velocity of riblets surface,a modified method was presented to obtain virtual origin and wall friction velocity together by least-squares fitting method,based on Spalding formula in the turbulent b...