Experimentally informed, linear mean-field modelling of circular cylinder aeroacoustics
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arXiv
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| Natura: | Preprint |
| Pubblicazione: |
2024
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| _version_ | 1866929317280219136 |
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| author | Prinja, Robin Jordan, Peter Margnat, Florent |
| author_facet | Prinja, Robin Jordan, Peter Margnat, Florent |
| contents | A noise modelling approach is proposed for bluff body wakes such as flow over a cylinder, where the primary noise source comprises large-scale coherent structures such as the vortex shedding flow feature. This phenomenon leads to Aeolian tones in the far-field, and is inherent in wake flows across a range of Reynolds numbers (Re), from low-Re to high-Re turbulent flows. The approach employs linear global stability analysis on the time-averaged mean flow, with amplitude calibration through two-point statistics, and far-field noise calculations from the global mode fluctuations by Curle analogy. The overall approach is tested for flow over a cylinder at Reynolds numbers Re=150 and 13300. For Re=150 flow, noise directivity calculations from the present approach agree with direct far-field computations. For Re=13300 flow, the mean flow is obtained by particle image velocimetry (PIV). The linear global mode for spanwise-homogeneous-type fluctuations is obtained at the main, lift fluctuation frequency. Calibration of this global mode involves Time-Resolved PIV data in the streamwise-spanwise plane, which is Fourier transformed in frequency-spanwise wavenumber space. The noise calculations for this global mode are then found to be less than 1 dB off from the microphone measurements. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2404_11434 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Experimentally informed, linear mean-field modelling of circular cylinder aeroacoustics Prinja, Robin Jordan, Peter Margnat, Florent Fluid Dynamics A noise modelling approach is proposed for bluff body wakes such as flow over a cylinder, where the primary noise source comprises large-scale coherent structures such as the vortex shedding flow feature. This phenomenon leads to Aeolian tones in the far-field, and is inherent in wake flows across a range of Reynolds numbers (Re), from low-Re to high-Re turbulent flows. The approach employs linear global stability analysis on the time-averaged mean flow, with amplitude calibration through two-point statistics, and far-field noise calculations from the global mode fluctuations by Curle analogy. The overall approach is tested for flow over a cylinder at Reynolds numbers Re=150 and 13300. For Re=150 flow, noise directivity calculations from the present approach agree with direct far-field computations. For Re=13300 flow, the mean flow is obtained by particle image velocimetry (PIV). The linear global mode for spanwise-homogeneous-type fluctuations is obtained at the main, lift fluctuation frequency. Calibration of this global mode involves Time-Resolved PIV data in the streamwise-spanwise plane, which is Fourier transformed in frequency-spanwise wavenumber space. The noise calculations for this global mode are then found to be less than 1 dB off from the microphone measurements. |
| title | Experimentally informed, linear mean-field modelling of circular cylinder aeroacoustics |
| topic | Fluid Dynamics |
| url | https://arxiv.org/abs/2404.11434 |