A hybrid method for sound scattering calculations is presented in this paper. The boundary element method (BEM) is combined with a recently developed edge source integral equation (ESIE) [J. Acoust. Soc. Am. 133, 3681-3691 (2013)]. Although the ESIE provides accurate results for convex, rigid polyhedra, it has several numerical challenges, one of which applies to certain radiation directions. The proposed method, denoted ESIEBEM, overcomes this problem with certain radiation directions by applying a similar approach as BEM. First, the sound pressure is calculated on the surface of the scattering object using the ESIE, and then second, the scattered sound is obtained at the receiver point using the Kirchhoff-Helmholtz boundary integral equation, as BEM does. The three methods have been compared for the scattering by a rigid cube. Based on results from several discretizations, ESIE and ESIEBEM results are typically (90% quartile) within 3-4 · 10 for a kL-value of 1.83 and 2 · 10 for kL = 9.15, L being the cube length, of reference results computed with the BEM. The computational cost of ESIEBEM appears to be lower than BEM.

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A hybrid method for acoustic scattering problems is studied in this paper. The boundary element method is combined with a recently developed edge diffraction based method [J. Acoust. Soc. Am. 133, pp. 3681–3691, 2013]. Although the edge diffraction method has been shown to provide accurate results for convex, rigid objects at a very attractive computational cost, it has some numerical challenges for certain radiation directions. The hybrid method suggested here has a similar structure as the boundary element method (BEM): in a first step, the sound pressure is calculated on the surface of the scattering object, and in a second step, the scattered sound is obtained at any external receiver point. In this method, the edge diffraction based method is used for the first step, and then, the calculation of the scattered sound is performed à la BEM by means of the Kirkhoff–Helmholtz Integral equation. Several benchmark cases are studied, and the results are compared with different reference methods.