Application of Finite Element Modeling to the Problem of Determining Hydrodynamic Noise Generated by Local Inhomogeneity

Abstract

Determining the hydrodynamic noise that occurs when various inhomogeneities of a body flow around a fluid is one of the most urgent problems of acoustics. The report presents a finite element method for determining the hydrodynamic noise, developed at the IAP RAS and implemented in the software “CATEC”. This method is based on the numerical solution of the Helmholtz equations in combination with boundary conditions on the scattering surface of the body and at infinity, which makes it possible to eliminate the most significant disadvantages of integral methods. The main disadvantages of integral methods are the inability to take into account the elasticity of a streamlined body, as well as re-reflection from a part of the body outside the control surface. Acoustic radiation in this case is defined as the result of the scattering of the pseudosonic field of turbulent sources on the surface of the body, which are the Lighthill tensor. The purpose of the report is to validate the method on the basis of experimental data on the noise emission of a cavity streamlined by an air flow, as well as to compare the results obtained with the solution by the integral FW-H method. The specificity of the problem is the noise of non-physical turbulence generated at the input boundary in the hydrodynamic part of the problem, and the need to filter it.