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Porous Sound-absorbing Material Model

1. miki model

Density and sound speed are required in Femet. Acquired specific acoustic impedance and complex wavenumber are transferred to effective density and complex sound speed using the following equations, (4) and (5).

 

 

2. JCA (Johnson-Champoux-Allard) model

 

Density and sound speed are required in Femet. Acquired effective density and bulk modulus are transferred to complex sound speed using the following equation, (8).

 

Note that atmospheric pressure and specific heat ratio are fixed to 101.3e3 [KPa] and 1.4, respectively, and the coefficient of kinematic viscosity and Prandtl number cannot be directly entered.

The coefficient of kinematic viscosity and Prandtl number are calculated by viscosity/density and viscosity×(specific heat/thermal conductivity)), respectively.

 

 

References:

[1] Miki Y., Acoustical properties of porous materials - Modifications of Delany-Bazley models, J. Acoust. Soc. Jpn (E). 11(1), 1990, pp. 19-24
[2] Miki Y., Acoustical properties of porous materials - Generalization of empirical models, J. Acoust. Soc. Jpn (E). 11(1), 1990, pp. 25-28

[3] Johnson D. L., Koplik J. and Dashen R., Theory of dynamic permeability and tortuosity in fluid-saturated porous media, J. Fluid Mech. 176, 1987, pp. 379-402
[4] Champoux Y. and Allard J.-F., Dynamic tortuosity and bulk modulus in air-saturated porous media, J. Appl. Phys. 70, 1991, pp. 1975-1979