%0 Journal Article
%T Application of Wavenumber-frequency Method for Characteristic Frequency Prediction of Cavity Noise at Subsonic Speeds
%J Journal of Applied Fluid Mechanics
%I
%Z 1735-3572
%A Lu, W.
%A Wei, L.
%A Wang, Y.
%A Yang, G.
%A Zheng, G.
%A Sun, Z.
%D 2023
%\ 12/04/2023
%V 17
%N 2
%P 370-383
%! Application of Wavenumber-frequency Method for Characteristic Frequency Prediction of Cavity Noise at Subsonic Speeds
%K Cavity noise
%K Flow-acoustic feedback
%K Wavenumber-frequency analysis
%K Pressure fluctuation
%K Flow instability
%R 10.47176/jafm.17.02.2081
%X Flow-acoustic feedback is one of the main types of noise in a cavity, is caused by the instability of the cavity shear layer and is enhanced through an acoustic-wave feedback mechanism. The flow characteristics of the cavity boundary/shear layer and the characteristic frequencies of the flow-acoustic feedback in the cavities are studied numerically, with aspect ratios ranging from 1/2 to 4/3. The freestream Mach number is equal to 0.11, corresponding to an Re-based cavity length of 2.1×105. Improved Delayed Detached Eddy Simulations combined with Ffowcs Williams-Hawkings acoustic analogy are used to simulate the flow and noise characteristics of the cavities. Auto-correlation analysis of flow field fluctuations is used to establish a link between the boundary/shear layer pressure fluctuations and flow-acoustic feedback noise. For the low aspect ratio cavities investigated in this paper, convection velocities along the shear layer development direction are obtained using wavenumber-frequency analysis. The deeper the cavity, the lower the shear layer flow velocity. Correspondingly, the characteristic frequencies of the narrowband noise generated by the flow-acoustic feedback shift linearly toward the low frequency band as the cavity depth increases. The results of the predicted noise characteristic frequencies obtained using wavenumber-frequency analysis and Rossiter's empirical formula are in agreement with the calculated results.
%U https://www.jafmonline.net/article_2351_126cc4e06026d2146fed589848aeb9a1.pdf