基于PIV测量的柔性壁减阻试验

Experimental investigation of drag-reducing for compliant wall by PIV measurement

为了解不同性能的柔性壁对湍流边界层的减阻效果,利用粒子图像测速技术(PIV)对刚性壁面与4种材料的柔性壁面的湍流边界层流向速度分量进行测量。从边界层速度分布求得壁面切应力的分布,并由此得到柔性壁与刚性平板的平均摩擦阻力系数。实验结果表明,柔性壁面的边界层速度分布在对数律上有所平移,具有特定性能的柔性壁具有一定的减阻作用。

For understanding the effect of compliant walls on drag reduction in turbulent boundary layer,the velocity profile in turbulent boundary layer over a rigid wall and six compliant walls is measured with the particle image velocimetry（PIV）. First,the shear stress profile alone the wall is calculated from the velocity profile in bounday layer, then the average skin friction coefficient of the rigid wall and compliant wall is calculated from the shear stress profile. The experimental result shows that, in boundary layer of turbulent flows over a compliant wall, compared with that over a rigid wall, the velocity profiles in log law region is extended further away from the wall. The experimental result confirms the effect of drag reduce for the special compliant coating surface of turbulent boundary layer.