Simultaneous Measurements of Velocity Fields at Two Vertically Crossing Planes by PIV Systems Using Polarization Technique

편광기법을 이용한 수직교차평면의 PIV 속도장 동시측정

A new PIV technique was developed for decreasing optical error which was created during simultaneous measurements of velocity fields at a wall-normal plane and wall-parallel plane by a plane PIV and a Stereoscopic PIV system. The two Nd:Yag laser systems and three CCD cameras were. synchronized to obtain instantaneous velocity fields at the same time. To avoid optical noise at the crossing line by the two laser light sheets, a new optical arrangement using polarization was applied. The obtained velocity fields show the existence of hairpin packet structure vividly and the idealized hairpin vortex signature is confirmed by experiment.