关键词: 喷流噪声, 噪声传播, 数值模拟, 伽辽金有限元法, 自由喷流

Abstract: The dynamic flow and distribution characteristics of the gas flow in the core region of a supersonic jet and its adjacent peripheral subsonic region are studied by using the numerical simulation method of an unsteady gas flow field. On these bases, the numerical simulation of the jet noise propagation and emission characteristics is completed by using the FWH method and the Galerkin finite element method in solving the Euler equation. The numerical simulation results show that the propagation area of the strong jet noise follows the free advancing jet flow front. After the free jet flow field is relatively stable, the propagation area of the strong jet noise is mainly at the end of the equal-energy zone of free jet flow, and some small scale tests also have strong jet noise near the shock wave system of the free jet flow. The strong jet noise is mainly caused by the large eddy dynamic suction driven by the free advancing jet flow front, the strong turbulence pulsation of the gas flow and the shock disturbance. Due to the influence of the grid resolution of numerical simulation, only the numerical simulation results of the middle and low frequency sound pressure levels can be kept generally close to the measured results.

Key words: Jet noise, Noise propagation, Numerical simulation, Galerkin finite element method, Free jet