The Effect of Water Quality Characteristics on Cavitation Noise
This study investigated the effects of seawater on cavitation noise using a water jet test, a two-dimensional wing test, and a three-dimensional wing test. A model propeller cavitation test was conducted in a cavitation tunnel using seawater, in order to determine the effects of propeller cavitation more precisely. In the cavitation tests, measured propeller performance for both cavitation noise inception and desinence, as well as the cavitation noise spectrum (see, for example, figure 7). On the basis of the results of the present propeller cavitation test and tests that were carried out previously, we discuss how to control the water quality in the cavitation tunnel to reproduce the cavitation phenomena, especially cavitation noise, in seawater (see, for example, figure 9).
Experimental Analysis and Simulation of Cavitating Throttle Flow
While there exist many papers on cavitating flow on large smooth streamlined bodies, very small geometries are less studied. In this paper, optical measurement techniques for local density and velocity distributions are used to analyze cavitating flow in micro geometries at the critical cavitation point. The experimental results are used for validation of the commercial CFD code ANSYS CFX-11. The consensuses as well as dierences of results are analyzed and discussed.
Cavitation Nuclei Population Dynamics in a Water Tunnel
The free stream nuclei number distributions in the Low Turbulence Water Tunnel at Caltech were measured using a Phase Doppler Anemometer. The changes in nuclei number distributions with water tunnel running time, with initial air content, with tunnel velocity varying from 2m/sec to 9m/sec and with water tunnel static tunnel pressures ranging from 40kPa to 110kPa were examined. Quite complex changes in nuclei number distributions were observed in the nuclei size range of interest from the point of view of cavitation, namely the range from 5 to 200[microns]. Order of magnitude changes were observed in the nuclei population.