Abstract: This paper aims at predicting the levels of the boundary layer noise as a function of the speed and the frequency, which based on the results obtained by flow-noise studies performed with a rotating cylinder in the boundary layer of the test section of water tunnel. The coating containing rich low surface energy materials is a hydrophobic and porous material. The covered coating model provides low dispersive and polar components of surface energy by decreasing bonds between water and coating, thus, the flow noise of the covered coating model can be decreased by 4~18dB in 4~80kHz.

Key words: coating surface, low surface energy, reduction of flow noise