Lattice Boltzmann simulation of sound absorption of an in-duct orifice
Date of Issue2013
International Congress on Acoustics (21st : 2013 : Montreal, Canada)
School of Mechanical and Aerospace Engineering
Two-dimensional time-domain numerical investigation of sound-induced flow through an orifice with a diameter 6mm is conducted by using lattice Boltzmann method. Emphasis is placed on characterizing its acoustic damping behaviors. The main damping mechanism is identified as incident waves interact with the shear layers formed at the orifices rims and the acoustic oscillations destabilize the shear layers to form vortex rings. And acoustic energy is converted into vortical energy. To quantify the orifice damping effect, power absorption coefficient is used. It is related to Rayleigh conductivity and describes the fraction of incident acoustical energy being absorbed. Numerical simulations are conducted in time domain by forcing a fluctuating flow with multiple tones through the orifice. This is different from frequency-domain simulations, of which the damping is characterized one frequency at a time. Comparing our results with those from Howe theoretical model, good agreement is observed. In addition, orifice thickness effect on its damping is discussed.
Proceedings of meetings on acoustics
© 2013 Acoustical Society of America. This paper was published in Proceedings of Meetings on Acoustics and is made available as an electronic reprint (preprint) with permission of Acoustical Society of America. The paper can be found at the following official DOI: [http://dx.doi.org/10.1121/1.4799686]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.