Study of Cavitation in Wakes of Circular Cylinders and Symmetric Wedges Using X-ray Densitometry

Cavitation in wakes behind canonical objects can exhibit variation in Strouhal number with a reduction in cavitation number. Circular cylinders of two diameters and symmetric wedges with a wedge angle of 15, 30, and 60 degrees are used to study cavitation in their wakes using X-ray densitometry. Using high speed video and X-ray densitometry, the nature of cavitation is studied in near-wake and a part of the far-wake region. In addition, acoustic measurements are also carried out to understand the spectral content of such wake cavities. Based on void fraction flow field and high-speed video measurements, the effect of cavitation on the K\'{a}rm\'{a}n vortex street spacing in the far wake region is studied. The results are the interpreted to explain the physical mechanisms responsible for the observed change in Strouhal number.