Simulations of cavity flow noise and turbulent jet noise using a hybrid method

Abstract

A hybrid method was explored to investigate the generation and near-field radiation of aerodynamic sound from an unsteady turbulent flow over a two-dimensional open cavity and three-dimensional jet flow. A two-dimensional cavity model was established to study the unsteady flow and radiated jet sound. It was revealed that the radiated sound that generated by the boundary layer separation and vortex impact cavity wall intervened in the front of the cavity, and an obvious interference phenomenon appeared. The far-field radiated sound generated by the cavity presented obvious directivity, and the sound pressure in the area located at 45°-135° interval was much higher. Then, the unsteady turbulence jet noises of the elliptical and rectangular nozzles were analyzed. It was revealed that the scale and intensity of the vortexes generated by the elliptical nozzle were larger than those by the rectangular nozzle. The jet noise of the elliptical nozzle is lower than that of the rectangular nozzle. Besides, the sound pressure distributions of the two nozzles presented obvious directivity. The sound pressure in the short-axis direction of the nozzle section was higher than that in the long-axis direction.