Prediction of hydrodynamic noise of open cavity flow |
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Authors: | Donghan Geng Yu Wang |
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Institution: | School of Mechanical Engineering, Tianjin University, Tianjin 300072, China |
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Abstract: | In this paper, the hydrodynamically generated noise by the flow over an open cavity is studied. First, aeroacoustic theories
and computational aeroacoustic (CAA) methodologies are reviewed in light of hydrodynamic acoustics, based on which, a hybrid
method is presented. In the coupling procedure, the unsteady cavity flow field is computed using large-eddy simulation (LES),
while the radiated sound is calculated by the Ffowcs Williams-Hawkings (FW-H) acoustic analogy with acoustic source terms
extracted from the time-dependent solutions of the unsteady flow. The hybrid LES-FW-H acoustic analogy method is tested with
an open cavity flow at Mach number of 0.006 and Reynolds number of 105. Following the reflection theorem of Powell, the contributions from different source terms are quantified, and the terms
involving wall-pressure fluctuations are found to account for most of the radiated intensity. The radiation field is investigated
in the frequency domain. For the longitudinal direction, the sound propagates with a dominant radiation downstream the cavity
in the near-field and a flatter directivity in the far-field, while for the spanwise direction, the acoustic waves have a
similar propagation along +z and ?z directions, with no visible directivity. |
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Keywords: | hydrodynamic acoustic open cavity large-eddy simulation acoustic analogy |
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