流场中3D3C速度矢量场检测方案

Tomographic PIV as a full volume 3D-3C flow field measurement technique can also be applied to thin sheets used in standard PIV. Tomographic PIV and Stereo PIV are compared with experimental data from an impinging jet in water. The field of view is 60 mm x 40 mm, the light sheet thickness is varied from 8 to 55 pixel. Images have been recorded with 4 cameras to gain results from two independent Stereo PIV systems and from Tomographic PIV using 2-4 cameras. Different error sources for both techniques are quantified. It is shown that instantaneous flow fields from Tomographic PIV deviate less from each of the two stereo systems, than the two stereo systems deviate from each other. A systematic error pattern is identified for the two stereo systems, which is not present for Tomographic PIV. Thin volume Tomographic PIV allows the calculation of multiple vector planes. Two planes can be calculated even for the thinnest light sheet (8 pixel) providing the full 3x3 strain-tensor. Thicker sheets with up to twelve vector planes allow the visualization of the small vortex structures in this experiment.