Propeller cavitation noise in hybrid viscous flow/FWH simulations using robust impermeable surface formulations

The recent years have seen increasing interest in the numerical evaluation of the underwater noise from cavitating propellers. When Ffowcs-Williams-Hawkings (FWH) based acoustic analogy methods are extended to cavity surfaces, the adequacy of different formulations is still debatable. The acoustic sources may be defined on either impermeable (or non-porous or solid) data surfaces which coincide with physical body surfaces; or on a permeable data surface that encompasses the entire noise generating flow region. In a permeable-FWH approach, the acoustic solution is dependent on the porous enclosure selected; and there is no unanimous agreement about its extent. In a viscous finite volume solver with impermeable-FWH approach, the acoustic effects of cavity fluctuations are not completely captured, due to the absence of any physical cavity surface within the simulations. In this paper, a novel hybrid approach is investigated, wherein the accuracy of the cavitation flow dynamics from a viscous CFD solver is combined with the simplicity of an acoustic source definition using impermeable surfaces. The flow simulations are performed in Star-CCM+ using incompressible two-phase Detached Eddy Simulations (DES) and the Schnerr-Sauer cavitation model. The instantaneous cavity surface geometry is extracted from the simulation results and used to define equivalent acoustic sources. The acoustic predictions from the model are verified by comparing with hydrodynamic pressure pulses from DES. Finally, the results are compared with experimental measurements, in order to evaluate the performance of each method.

Subjects

permeable FWH

impermeable FWH

cavitation noise

underwater acoustics

URN

DDC Class

620: Engineering

Publication version

publishedVersion

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http://rightsstatements.org/vocab/InC/1.0/

Name

Tomy-PropellerCavitationNoiseInHybridViscousFlowfwhSimulationsUsingRo-1173-1-final.pdf

Type

Main Article

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1.83 MB

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Propeller cavitation noise in hybrid viscous flow/FWH simulations using robust impermeable surface formulations