Reconstruction of ultrasonic wavefronts from the field of the circular transducer

Abstract

This paper is concerned with reconstruction of wavefronts of ultrasonic waves. New method for the reconstruction of wavefronts of ultrasonic waves from data collected at discrete points in a fixed plane, perpendicular to a propagation direction, has been proposed. The accuracy of the method was determined comparing the reconstructed wavefronts with those obtained theoretically from a model of the baffled piston type circular transducer. From the results presented it is seen, that shape of the wavefront depends on the distance between the wavefront and a transmitter. The computed wavefronts can be analyzed in terms of plane and edge waves radiated. It was established, that in the near field zone, with uncertainty less than 0.1l, wavefronts can be assumed to be the combination of the plane and spherical wavefronts. In the intermediate zone, in the geometrical beam region, wavefronts can be assumed to be spherical. Outside the geometrical beam region, due to edge waves, form of the wavefront becomes complex, and it can not be approximated to simple curves. In the far field zone, with uncertainty less than 0.05l, wavefronts can be assumed to be spherical wavefronts.