Noise Power Prediction of Air Flow with Obstruction through Subsonic Wind Tunnel

This paper estimates noise power generated by a turbulent air flow in a duct from the knowledge of mean quantities (average velocity and sound pressure level). The sound excitation by fluid flow through duct can be used to predict fluid behavior. However, the fluid flow container stability has to be taken in account simultaneously with fluid flow effect on sound generation and propagation. The experimental system used in this work is air flow through subsonic wind tunnel duct. The sound pressure levels of air flows through test section of subsonic wind tunnel (at three air flow velocities 2.5, 7.3 and 12.5 m/s) respectively were carried out experimentally. The sound excitation or generation by air flow throughout the test section of subsonic wind tunnel without any obstruction can't be used to imagine the fluid behavior. To predict fluid flow properties, an infinite cylinder was immersed in order to obstruct the air flow and generate new source of sound. This case is relevant to a wide range of engineering applications including aircraft landing gear, rail pantographs and automotive side-mirrors. The results discuss the effect of Reynolds number on the sound generation, propagation features and vice-versa. The results are compared with other researchers which gives a good agreements.