Flow noise measurements at strong tidal current area in Uldolmok Waterway

Abstract

Flow noise is a kind of hydrodynamic noise, which is created by turbulent flow in the boundary layer around the hydrophone. Although the turbulent pressure is not a true acoustic noise in that its influence decreases rapidly with distance, it acts as a self-noise source. In general, since the spectrum level of flow noise has been reported to increase rapidly with the increment of flow speed, it is possible to monitor the current velocity from the flow noise measurements. Uldolmok waterway in Korea is one of the locations where currents are very strong, with maximum speed of about 5 m/s. The measurements of flow noise were conducted in Uldolmok waterway using two different shapes of hydrophone. In this talk, the flow noise spectra for various flow speeds will be presented for the frequency range of 20-100 Hz, and the comparison of spectra between two different-shape hydrophones will be given. © 2013 Acoustical Society of America.