• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.658-663
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• 2013

A new formulation of the MNDIF method is introduced to extract highly accurate eigenvalues of concave acoustic cavities with arbitrary shapes. It is said that the MNDIF method cannot yield accurate eigenvalues for concave cavities. To overcome this weak point, a new approach of dividing a concave cavity into two convex domains is proposed. The validity of the proposed method is shown through a case study.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.11
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• pp.1003-1011
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• 2013

A new formulation of the MNDIF method is introduced to extract highly accurate eigenvalues of concave acoustic cavities. Since the MNDIF method, which was introduced by the author, can be applicable for only convex acoustic cavities, a new approach of dividing a concave cavity into two convex domains and formulating an algebraic eigenvalue problem is proposed in the paper. A system matrix equation, which gives eigenvalues, is obtained from boundary conditions for each domain and the condition of continuity in the interface between the two domains. The validity and accuracy of the proposed method are shown through example studies.

• The Journal of the Acoustical Society of Korea
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• v.16 no.5
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• pp.60-67
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• 1997

the famous King Song-dok Bell which was cast in A.D. 771, during Silla dynasty has significant xize of concave cavity which acts as Helmholtz resonator on the ground. To see the effect of this cavity and the bell's internal acoustic cavity on radiating sound of bell, three dimensional measurement of internal sound field was performed. In this paper, the dtail measurement procedure and results are carefully addressed. The effect of the cavity on the radiating sound of bell is investigated using simple and physically representative model. A new size of cavity is proposed.