As one of the basic acoustic parameters, the speed of sound is of great importance when considering acoustic effect. This paper explores the equivalent speed of sound, when the structure is modelled as a homogeneous fluid, for a periodic arrangement of a waveguide with alternating channel height similar to a honeycomb structure with open cells. Numerical simulation shows that the equivalent speed of sound is lower than that of pure air and the most important parameter is the height ratio of the waveguide. The lower speed of sound is caused by the increased inertial effect. This inertial effect can be precisely interpreted by the classic concept of tortuosity, which depicts the effect of tortuous fluid path.
Equivalent speed of sound Periodic Waveguide structure
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The project is supported by a China National Key Basic Research Scheme, or “973” scheme (2012CB7202). The first author also acknowledges the support of the PhD studentship from the University of Hong Kong.
Allard J, Atalla N (2009). Propagation of sound in porous media: modelling sound absorbing materials, 2nd edn. Wiley, New yorkGoogle Scholar
Christensen J, Huidobro PA, Martin-Moreno L, Garcia-Vidal FJ (2008) Confining and slowing airborne sound with a corrugated metawire. Appl Phys Lett 93(8):083502CrossRefGoogle Scholar
Johnson DL, Plona TJ, Scala C, Pasierb F, Kojima H (1982) Tortuosity and acoustic slow waves. Phys Rev Lett 49(25):1840CrossRefGoogle Scholar
Johnson DL, Sen PN (1981) Multiple scattering of acoustic waves with application to the index of refraction of fourth sound. Phys Rev B 24(5):2486CrossRefGoogle Scholar
Krokhin AA, Arriaga J, Gumen LN (2003) Speed of sound in periodic elastic composites. Phys Rev Lett 91(26):264302CrossRefGoogle Scholar
Landau LD, Lifshitz EM (1987) Fluid mechanics, vol 6. Course of theoretical physics, pp 26–30Google Scholar
Santillán A, Bozhevolnyi SI (2014) Demonstration of slow sound propagation and acoustic transparency with a series of detuned resonators. Phys Rev B 89(18):184301CrossRefGoogle Scholar
1.Lab of Aerodynamics and Acoustics, Zhejiang Institute of Research and Innovation, Shenzhen Institute of Research and Innovation, Department of Mechanical EngineeringThe University of Hong KongHong KongChina