Use of a transient wave propagation code for 3D simulation of cw radiated transducer fields

• Published in: Ultrasonics Vol. 37; no. 2; pp. 89 - 96
• Main Authors: Schechter, R.S., Simmonds, K.E., Batra, N.K., Mignogna, R.B., Delsanto, P.P.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.02.1999; Elsevier Science
• Subjects: Acoustics; Exact sciences and technology; Finite differences; Fundamental areas of phenomenology (including applications); Numerical simulation; Parallel computing; Physics; Radiated fields; Transducer; Transduction; acoustical devices for the generation and reproduction of sound; Transducer; Numerical simulation; Parallel computing; Radiated fields; Finite differences; Far field; Numerical method; Acoustic field; Experimental study; Immersion test; Three dimensional model; Continuous wave; Time domain method; Massive parallelism; Acoustic radiation; Ultrasonic transducer; Finite difference method
• ISSN: 0041-624X; 1874-9968
• DOI: 10.1016/S0041-624X(98)00053-5

In order to compute continuous wave (cw) ultrasonic wave fields in complex media, where analytical approaches are extremely difficult, numerical simulations on large computational grids must be employed. The use of a time domain code, normally used for transient wave propagation in heterogeneous media, is used here as a tool to simulate continuous wave fields. As a starting point, the case of the three-dimensional pressure field radiated from a circular aperture in water is computed. These numerical simulations are performed on a massively parallel computer and compared with experiment and known theory. The computations are performed on very large three-dimensional grids that span the near to the far field. As a trial case, a numerical computation of the radiated field from a continuous-wave excited transducer in a baffle is compared with an analytical evaluation using the Rayleigh surface integral and experiment. In addition, results are presented that show the effect of a small defect placed in the beam. To do this, a small cylindrical copper scatterer was placed in the near field, in both the computation and an accompanying experiment. These cases are done in preparation for using the same approach for computing cw fields radiated from a transducer into complex heterogeneous media.