镜像互换法在PIV 近壁测量中的应用

The strong velocity gradient near the wall limits the improvement of the accuracy of Particle Image Velocimetry (PIV) measurement. With the development of the digital image deform method, the rise of Window Deformation Iterative Multigrid (WIDIM) and Interface-PIV (IPIV) improved this problem to some extent, but the measurement accuracy should be and can be further improved. This paper presents a new pre-processing method for the particle images, i.e., Mirror Interchange (MI) method. By reconstructing the antisymmetric velocity field, this method can match the non-slip wall boundary condition and can eliminate the calculation error of the discrete velocity gradient in the normal direction. Hence, compared with other pre-processing methods, the MI method can further improve the measurement accuracy and uncertainty. Finally, this method is successfully applied in the measurement of a compressor cascade.