Cavitation inception in quiescent and co-flow nozzle jets

Abstract

The prediction and scaling of cavitation inception in jets remains a difficult task. This paper presents findings of an experimental investigation to study the cavitation inception of quiescent and co-flow submerged jets. Experimental data were collected in the ARL/PSU 12-inch and 48-inch Diameter Water Tunnels. A submerged nozzle was mounted axially along the centerline of the test section with jet mass flow supplied using an external pump. The setup allowed for independent control of both jet and freestream velocities. Observations of cavitation patterns, inception locations and cavitation inception numbers for quiescent (VR=V∞/Vjet=0), near-quiescent (0 0.1) operating conditions were recorded. Data were measured using two- 25.4mm and one- 101.6mm diameter axisymmetric nozzles. Visual observations of cavitation indicated that the cavitation occurs in different location for co-flow jets compared to quiescent jets. PIV measurements show that different flow mechanisms are responsible for this cavitation inception. © 2010 Publishing House for Journal of Hydrodynamics.