Cavitation streamlining of a round cylinder in the critical range

Abstract

Abstract The paper presents experimental results on the transverse cavitation streamlining of a circular cylinder by a turbulent water flow in the critical range of Reynolds numbers determined on diameter. Using the PIV method, averaged velocity fields are obtained. Their vector patterns serve to determine the lengths of the reverse flow and the distance between vortices in the near wake behind the cylinder. The presence of a minimum of spatial characteristics of the vortex zone for the initial cavitation modes is shown. Initial cavitation, transient modes, and developed cavitation are determined for different flow rates. The beginning of cavitation is found to depend on the Reynolds number. With smooth decrease in static pressure in front of the cylinder, critical anomalous phenomena, probably related to the rearrangement of cavitation modes, are detected in very narrow range. Vortex shedding from the cylinder surface is found to occur quasi-periodically despite the possibility of simultaneous shedding and breakdown of vortices.