流体中2D3C速度矢量场,时间分辨速度矢量场检测方案(粒子图像测速)

In the last years, several techniques have been developed and improved in such a way that it is possible to measure the three velocity components in a flow. Some techniques as Stereoscopic PIV or holographic PIV are well known. Others, like tomographic PIV started to develop more recently. Stereoscopic Particle Image Velocimetry (SPIV) or Tomographic PIV need a complex set-up, involving flow visualization with several cameras, and present important restrictions when applied to confined liquid flows. Others like Holographic PIV cannot be applied in flows with a high particle density. Here a new technique, called High Speed Digital Image Plane Holography has been developed for the measurement of the three velocity components in a complex geometry brain aneurysm model using a configuration similar to regular PIV. This was done by using a two cavity high speed laser, one double frame high speed camera and normal visualization. The two in-plane velocity components were obtained from the holograms reconstructed intensity distribution using a PIV analysis. The out-of plane component was obtained from the reconstructed phase differences using an interferometric method. Due to the laser short coherence length, a portable and compact system has been built in order to be able to the measure larger fluid areas.