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).
Evaluation of the cavitation inception speed of the ship propeller using acceleration on its adjacent structure
Cavitation noise is strongly restricted by the Navy because this noise can be detected by the sonar systems installed on enemy ships to locate a ship. When cavitation is started, the high-frequency broadband noise increases modulated with shaft rotation and propeller blade passing frequencies. Therefore, the Cavitation inception speed (CIS) is typically detected using the Detection of envelope modulation on noise (DEMON) analysis to identify the underwater propeller noise. Since the CIS varies based on the ship’s condition and sea state, realtime CIS monitoring is required. In this paper, a CIS detection method that evaluates the acceleration on the hull adjacent to the propeller was proposed and verified through experimentation.
Influence de la chute d"essai et de la nucléation sur les performances en cavitation des modèles de turbines Francis.
Note: Using Smart Source Parsing pp. 15 .- + version anglaise 3 Reference LMH-CONF-1986-004 Record created on 2005-11-04, modified on 2017-08-21