A numerical study of transient flow around a cylinder and aerodynamic sound radiation

J. C. Cai, J. Pan, A. Kryzhanovskyi

Research output: Contribution to journalArticle

Abstract

The fully 3D turbulent incompressible flow around a cylinder and in its wake at a Reynolds number Re = = 9×104 based on the cylinder diameter and Mach number M = 0.1 is calculated using Large Eddy Simulations (LES). Encouraging results are found in comparison to experimental data for the fluctuating lift and drag forces. The acoustic pressure in far-field is commutated through the surface integral formulation of the Ffowcs Williams and Hawkings (FWH) equation in acoustic analogy. Five different sound sources, the cylinder wall and four permeable surfaces in the flow fields, are employed. The spectra of the sound pressure are generally in quantitative agreement with the measured one though the acoustic sources are pseudo-sound regarding the incompressible flow simulation. The acoustic component at the Strouhal number related to vortex shedding has been predicted accurately. For the broad band sound, the permeable surfaces in the near wake region give qualitative enough accuracy level of predictions, while the cylinder wall surface shows a noticeable under-prediction. The sound radiation of the volumetric sources based on Lighthill tensors at vortex shedding is also studied. Its far-field directivity is of lateral quadrupoles with the weak radiations in the flow and cross-flow directions.

Original languageEnglish
Pages (from-to)331-346
Number of pages16
JournalThermophysics and Aeromechanics
Volume25
Issue number3
DOIs
Publication statusPublished - 1 May 2018

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aerodynamics
acoustics
radiation
vortex shedding
incompressible flow
far fields
near wakes
Strouhal number
cross flow
directivity
large eddy simulation
sound pressure
predictions
Mach number
wakes
drag
Reynolds number
flow distribution
quadrupoles
tensors

Cite this

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A numerical study of transient flow around a cylinder and aerodynamic sound radiation. / Cai, J. C.; Pan, J.; Kryzhanovskyi, A.

In: Thermophysics and Aeromechanics, Vol. 25, No. 3, 01.05.2018, p. 331-346.

Research output: Contribution to journalArticle

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