Experimental investigation of near-wake characteristics of hydrodynamic cavitating flow around circular cylindrical pins of different geometries with and without ultrasonic transducers

The primary objective of this research is to study the hydrodynamic cavitating effects of fluid flow past a circular cylindrical pin of different geometries. An experimental investigation is carried out to study the effect of cylinder diameter and its length on the formation of wake cavitation in the upper sub-critical flow regime, which corresponds to Reynolds number (Re) in the range of 2 x 10(4) to 2 x 10(5). The vapour volume fraction was found to increase with a decrease in the cavitation number. The pressures in the cavitating region were found to be fluctuating and the Strouhal number was calculated. Additionally, to enhance the cavitation phenomena, an ultrasonic transducer is designed. Results reported that with an increase in the cavitation number, the size of the wake cavity decreased. Also, the size and the length of the wake cavity depend on the diameter of the cylinder and the size of the step provided. However, with an ultrasonic transducer, the time for inception cavitation decreases, and the noise level increases.