ASYMPTOTIC APPROXIMATION OF THE MODAL ACOUSTIC IMPEDANCE OF A CIRCULAR MEMBRANE

作者：Rdzanek Wojciech P^*; Rdzanek Witold J; Szemela Krzysztof

来源：Journal of Computational Acoustics, 2010, 18(4): 335-362.

DOI：10.1142/S0218396X1000422X

• Modal acoustic impedance
• acoustic attenuation
• Green function
• asymmetric asymptotics
• time harmonic steady-state vibrations
• eigenfunctions
• eigenfrequencies
• sound radiation

The Neumann boundary value problem of the Helmholtz equation of a vibrating circular membrane embedded into a flat rigid baffle is solved. The membrane is excited asymmetrically and radiates acoustic waves into the half-space above the baffle. A set of elementary asymptotic equations for modal radiation self-impedance and mutual impedance is presented. The equations are necessary for numerical computations of the radiated active and reactive acoustic power including the acoustic attenuation. A few equations available in the literature are collected. All the missing equations have been obtained using the methods of analysis of contour integral and stationary phase. The presented equations cover a wide frequency band, with the exception of the lowest frequencies and the frequencies close to coincidence.

• 出版日期2010-12