Flow structure and flow-induced noise in an axisymmetric cavity with lids
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- Jung, S.Y. & Sung, H.J. J Mech Sci Technol (2016) 30: 3229. doi:10.1007/s12206-016-0631-6
Direct numerical simulations of incompressible turbulent flow through an axisymmetric cavity with or without lids were performed at Ret,in = 186 to examine the hydrodynamic effects of the lids on the flow-induced noise. The strength of the recirculation in the downstream region was weakened by the installation of the lids. Comparison of the acoustic sources of the Lighthill equation indicated that the lid in the downstream region attenuated the flow-induced noise substantially. Frequency spectra and spatio-temporal correlations of pressure fluctuations revealed the most energetic mode and the convective nature of the flow over the cavity. It was evident from a detailed investigation of the instantaneous flow fields that the introduction of lids into the cavity significantly weakened the interaction between the separated shear layer and the trailing edge of the cavity. The present results clearly showed that the installation of lids is an effective means of reducing flow-induced noise.