Theoretical Prediction of the Acoustical Nonlinear FieldRadiated from a Concave Focusing Source with a Wide Aperture Angle

Abstract

We propose a time-domain theoretical approach topredict the acoustic nonlinear field radiated from a concave focusingspherical source with a wide aperture angle. The nonlinear soundpropagation is theoretically described by an accurate mathematicalmodel including the continuity and momentum equations. Numericalcalculation is implemented by using the finite difference time domainalgorithm in the oblate spheroidal coordinate system. To examine thevalidity of the theoretical model, we calculate the sound fieldsradiated from concave spherical focusing transducers with apertureangles 30° and 40° and the results are compared withthose obtained by the SBE solution.