Title: A two-dimensional computational study of the flow effect on the acoustic behaviour of Helmholtz resonators

Authors: Asim Iqbal, Ahmet Selamet

Addresses: Department of Mechanical Engineering, The Ohio State University, E 513 Peter L. and Clara M. Scott Laboratory, 201 West 19th Avenue, Columbus, OH 43210-1142, USA. ' Department of Mechanical Engineering, The Ohio State University, E 509 Peter L. and Clara M. Scott Laboratory, 201 West 19th Avenue, Columbus, OH 43210-1142, USA

Abstract: Impact of mean flow on the acoustic attenuation performance of a Helmholtz resonator is investigated computationally. To determine the time-dependent flow field, two-dimensional unsteady, turbulent, and compressible Navier-Stokes equations are solved. Pressure obtained from the flow field is used to calculate the Helmholtz resonator|s transmission loss at different velocities. Increasing the mean flow velocity in the main duct is shown computationally to reduce the peak transmission loss in general and force a shift in the fundamental resonance frequency to a higher value. These predictions are consistent with the trends observed in the experimental studies available in the literature. Also, at discrete Strouhal numbers, the simulations capture the flow-acoustic coupling which transforms the Helmholtz resonator essentially to a noise generator. The approach presented here demonstrates the ability of a numerical tool to study the complex interactions of the flow field with the acoustics of Helmholtz resonators effectively.

Keywords: Helmholtz resonators; flow effect; transmission loss; CFD; computational fluid dynamics; mean flow; acoustic attenuation performance; noise generators; acoustics.

DOI: 10.1504/IJVNV.2010.036682

International Journal of Vehicle Noise and Vibration, 2010 Vol.6 No.2/3/4, pp.130 - 148

Available online: 05 Nov 2010 *

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