Experimental Study on the Reduction of Flow Noise Due to Low Surface Energy Coating
Tian Jun  Xue Qunji
(Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences 730000)

Abstract: Acoustic communication through the water medium is greatly handicapped by the noise produced by the moving vehicle and its machinery. At high speeds, the flow noise seems to mask all other components of noise. This study presents a first attempt to predict the levels of the boundary layer noise and noise produced by a coating composed of low surface energy as a function of the flow speed and the noise frequency on the basis of the results obtained by flow-noise experiment performed with a rotating cylinder in a water tunnel. We investigate the tensile strength of the bond between water and coating materials. The results are compared with that measured previously with an Al alloy model. Large difference is found between Al model and that covered with low surface energy coating. The coating model contributed to its low dispersive and polar components of surface energy by decreasing bond between water and coating and increasing the boundary layer thickness, thus, it decreases the flow noise.
Keywords: low surface energy reduction of flow noise.