In this study, the method of a smoothed corner that replaces a commonly used sharp convex corner is employed for noise reduction. The effects of the two parameters — the smoothing angle and the radius of the smoothed surface on the flow structure are investigated. It is found that the larger smoothing angle and the larger radius of the smoothed surface can decrease the strength of the vortex induced by the blast-wave diffraction. In some circumstances, it is found that there is no vortex induced by the blast-wave diffraction. To study the noise reduction, the circumferential pressures at the distances of r = 2D and 4D are measured. The computational results show that the smoothed corner can effectively weaken the vortex strength, and consequently can successfully reduce the noise resulted from the blast wave diffraction around the duct exit. exit
Noise Reduction Vortex Strength Shock Mach Number Secondary Shock Maximum Vorticity
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M.J. Lighthill: The diffraction of blast. I. Proc. Royal Soc. London, Series A 198, 454 (1949)Google Scholar
A.D. Jones: Modeling the exhaust noise radiated from reciprocating internal combustion engines: A literature review. Noise Control Eng. J. 23(1), 12 (1984)MathSciNetCrossRefGoogle Scholar
J.T. Kim, Y.M. Kim, J.S. Maeng, M.S. Lyu and Y.G. Ku: Unstructured grid finite volume analysis for acoustic and characteristics in exhaust silencer systems. Numerical Heat Transfer, Part A 30(5), 439 (1996)ADSCrossRefGoogle Scholar
H.D. Kim and T. Setoguchi: Study of the discharge of weak shocks from an open end of a duct. J. Sound and Vibration 226(5), 1011 (1999)ADSCrossRefGoogle Scholar
J. Higashiyama and J. Iwamoto: Experimental study of exhaust noise generated by pulsating flow downstream of pipe end. JSAE Review 20, 73 (2000)CrossRefGoogle Scholar
M. Endo, Y. Futagami and J. Iwamoto: Relation between the flow pattern downstream of the duct and the noise. JSAE Review 21, 125 (2000)CrossRefGoogle Scholar