Indian Institute of Technology Kanpur
We are interested in a certain class of bifacial Indian drums, such as dholak, pakhawaj, and mrdangam, which consist of composite circular membranes stretched over an enclosed air cavity on both sides of an axisymmetric wooden shell. There is a large variety of such drums in Indian music which differ from each other in shapes and sizes of the shell and in the nature of the composite membranes. These drums produce sounds which have a definite pitch and hence can be qualified as musical in nature. Whereas, the effect of the composite nature of the membrane is well studied in the context of the monofacial Indian drum tabla, the acoustical implications of the coupling between two composite membranes (of different material and geometric properties) through an air cavity remains unexplored. The purpose of this work is to study this acoustical problem using a finite element method based numerical methodology. The aim is to solve the coupled structural acoustic boundary-value-problem for the enclosed air pressure and the membrane vibration. In our detailed investigation, we will study the effect of cavity size and shape, as well as the properties of the composite membranes, on the acoustics of the bifacial drums.
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