Preliminary Experimental results are presented on the application of Particle image velocimetry (PIV) in a Mach 3 flow produced in a Ludwieg tube facility. The transitory nature of the flow places high demands on the required hardware performance and presents a challenge to the seeding process. A Nd:YLF laser with a pulse rate of 3 KHz and a CMOS camera with interframe time of 2 s along with TiO2 nanoparticles were selected, allowing the capture of the nozzle starting process. Best seeding results were achieved by fil領(lǐng) the entire charge tube with a mixture of seeding particles and charge gas prior to tunnel startup. The starting shocks unsteady motion and the large scale structure were well resolved, and agreement was found between the velocity history from PIV and the wall pressure signal. The starting normal shock wave was used to determine the seeding particle performance parameters. In addition, an evaluation of the boundary layer profile developed over an axisymmetric body at Reynlods number of 2×107 was obtained and compared favorably to CFD results. 時間分辨粒子成像測速系統(tǒng)(TR-PIV) 用于粒子成像測速(PIV)的熒光示蹤粒子 HighSpeedStar PIV相機