{"title":"Acoustic Analysis with Consideration of Damping Effects of Air Viscosity in Sound Pathway","authors":"M. Sasajima, M. Watanabe, T. Yamaguchi, Y. Kurosawa, Y. Koike","volume":78,"journal":"International Journal of Mechanical and Mechatronics Engineering","pagesStart":1327,"pagesEnd":1333,"ISSN":"1307-6892","URL":"https:\/\/publications.waset.org\/pdf\/8614","abstract":"Sound pathways in the enclosures of small earphones\r\nare very narrow. In such narrow pathways, the speed of sound\r\npropagation and the phase of sound waves change because of the air\r\nviscosity. We have developed a new finite element method that\r\nincludes the effects of damping due to air viscosity for modeling the\r\nsound pathway. This method is developed as an extension of the\r\nexisting finite element method for porous sound-absorbing materials.\r\nThe numerical calculation results using the proposed finite element\r\nmethod are validated against the existing calculation methods.","references":"[1] T. Yamaguchi, J. Tsugawa, H. Enomoto and Y. Kurosawa, \"Layout of\r\nSound Absorbing Materials in 3D Rooms Using Damping Contributions\r\nwith Eigenvectors as Weight Coefficients\", Journal of System Design and\r\nDynamics, Vol. 4-1, pp. 166-176, 2010.\r\n[2] T. Yamaguchi, Y. Kurosawa and H. Enomoto, \"Damped Vibration\r\nAnalysis Using Finite Element Method with Approximated Modal\r\nDamping for Automotive Double Walls with a Porous Material\", Journal\r\nof Sound and Vibration, Vol. 325, pp. 436-450, 2009.\r\n[3] M. Sasajima, T. Yamaguchi and A. Hara, \"Acoustic Analysis Using\r\nFinite Element Method Considering Effects of Damping Caused by Air\r\nViscosity in Audio Equipment\", Applied Mechanics and Materials, Vol.\r\n36, pp. 282-286, 2010.\r\n[4] H. Utsuno, T. Tanaka, Y. Morisawa and T. Yoshimura, \"Prediction of\r\nNormal Sound Absorption Coefficient for Multi-Layer Sound Absorbing\r\nMaterials by Using the Boundary Element Method\", Transactions of\r\nJapan Society of Mechanical Engineers, Vol. 56-532C, pp. 3248-3252,\r\n1990.\r\n[5] A. Craggs and J.G.Hildebrandt, \"Effective densities and resistivities for\r\nacoustic propagation in narrow tubes\", Journal of Sound and Vibration,\r\nVol.92, pp321-331, 1984.\r\n[6] M. A. Biot, \"Theory of Propagation of Elastic Waves in a Fluid-Saturated\r\nPorous Solid. \u00d4\u00e0\u00ed. Higher Frequency Range\", Journal of the Acoustical\r\nSociety of America, Vol.28, pp179-191, 1956.","publisher":"World Academy of Science, Engineering and Technology","index":"Open Science Index 78, 2013"}