Analysis Of Flow Noise Base On The PIV Measure

The researches of objects'radiated noise in the water have been hot issues in the field of underwater acoustic. The research of radiated noise includes reducing and measuring it, the former is aimed at strengthening the concealment of underwater pilot and the purpose of the latter is that detects,locates,identifies and tracks the target through measuring radiated noise. Common radiation noise measurement method is the use of hydrophones, vector hydrophone and hydrophone array-based to measure directly. Though these methods can directly measure the objects'radiated noise, they must put the measuring equipment directly into water. While the recently developing technology of particle image velocity can make up the deficiencies of measuring the radiated noise by hydrophone.This paper firstly gives the object tail trailing edge noise radiation in the air empirical formula in theory because the purpose of this paper is to study its applicability in the water. Secondly, use the gravitational low noise water tunnel test condition and the system of PIV to measure the torpedo model and shell model to get the radiated noise and three-dimensional velocity in their tail edge in different flow rates. Finally, form analysis and processing a large number of measurement dates, obtain the models'sound pressure radiated noise power spectrum as well as the tail of the plane hydrophone flow field inside the three-dimensional velocity vector distribution at different flow rates. From the calculating result we can see that if modify the empirical formula of tail trailing edge noise radiation in the air in some sort so that we can give the empirical formula of the object tail trailing edge noise radiation in the water. Then summarize the work of the test and recommend ways to improve the test.