Mathematical modeling and decomposition ofhydrodynamics-acoustic fields using perturbationmethods

Conservation of mass, momentum, energy and state equations are recognizedas basic mathematical models in analysis of the acoustic behavior of cavitation, as wellas supercavitation. also, it is known that the order of acoustic eects is not as high asthat of hydrodynamics. therefore, in this paper, initially, for comparing dierent terms ofequations, using scale analysis, conservation equations are converted into dimensionlessones. then, by comparing all conditions, coupled with weighting terms available inthose equations, groups of parameters most appropriate with the hydrodynamics andhydroacoustics of the cavitating ow, are selected. by regarding acoustics as lowerorder phenomena, compared to the hydrodynamics of ow, and simultaneously using theperturbation method, two equations containing leading and rst orders and dierent termscan be attained. obtained results indicate that leading order equations represent thehydrodynamics of the cavitating ow, and rst order equations indicate the acoustics ofcavitation or supercavitation. acoustic equations of the present study contain terms relatedto uid viscosity, density and pressure changes, and background ow velocity. as acousticequations are coupled with leading order equations, in order to nd the noise of cavitation,equations of uid ow for compressible ow should be resolved