流场中3D3C速度矢量场检测方案(粒子图像测速)

The Tomographic-PIV measurement system performances are experimentally assessed within the present study. The technique is applied to the turbulent air flow past circular cylinders in two configurations, namely the thin light sheet and the thick light sheet. In the first case the Tomo-PIV measurements are compared with stereoscopic PIV, which is assumed as a reference result. Image signal conditioning by pre-processing seems to be essential in order to achieve an accurate particle field reconstruction in presence of background light and electronic noise. The comparison shows that the two techniques are basically equivalent in the thin light sheet configuration. The 3D measurements are performed with the thick light sheet technique where the instantaneous velocity vector distribution is measured over a domain of 31x26x10 mm3 yielding 28x24x5 velocity vectors. The vortex wake past a circular section cylinder is visualized within the volume snapshots and the time-averaged flow representation shows a consistent flow pattern with respect to the geometric boundary conditions with the separated shear layers aligned along the cylinder axis.