A204 スキャニング・ステレオPIVによる軸対称噴流の三次元渦度計測

A scanning stereo particle image velocimetry (SSPIV) system was developed to measure the three-dimensional (3D) distribution of three-component (3C) velocity in a turbulent round jet. A laser sheet produced with a high-repetition-rate pulsed Nd:YLF laser was scanned by an optical scanner in a direction normal to the sheet. Two high-speed mega-pixel resolution C-MOS cameras captured the particle images illuminated by the light sheet, and the stereoscopic PIV method was adopted to acquire the 3D-3C velocity distribution of turbulent water flow. A water jet formed by a round nozzle with an exit diameter of D=5 mm was diagnosed by the current technique. The jet Reynolds number was set at Re ?? 1000, and streamwise locations of measurement were fixed at x=40D. A measurement volume (-100 × 100 × 100 mm 3) containing 50 velocity planes was scanned in 0.208 s, which was sufficiently short to capture the instantaneous vortical structures. The iso-vorticity surfaces clearly depict vortical structures in the jet shear layer. Development of the vortical structure was also observed by continuous laser sheet scanning.