Node based Method of Moments Solution to Combined Layer Formulation of Acoustic Scattering
B. Chandrasekhar

Source CMES: Computer Modeling in Engineering & Sciences, Vol. 33, No. 3, pp. 243-268, 2008
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Keywords Acoustic scattering, Method of moments, Node based basis function, Boundary integral equations, Acoustic resonance problem, Non-uniqueness.
Abstract In this work, a novel numerical technique, based on method of moments solution, is presented to solve the Combined layer formulation (CLF) to insure unique solution to the exterior acoustic scattering problem at all frequencies. A new set of basis functions, namely, Node based basis functions are used to represent the source distribution on the surface of rigid body and the same functions are used as testing functions as well. Combined layer formulation (CLF) is defined by linearly combining the Single layer formulation (SLF) and Double layer formulation (DLF) with complex coupling parameter. The matrix equations for the SLF and DLF are derived and same equations are extended to the CLF. The surface of the body is modeled by triangular patch modeling. Results of numerical technique presented in this paper, using node based basis functions, are compared with the exact solutions wherever available. Also, condition numbers of the impedance matrices of SLF, DLF and CLF are plotted, for some objects of canonical shapes, to show that only CLF is free from resonance problem.
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