Alan K. Walden
Thomas R. Howarth
Naval Res. Lab., Underwater Sound Reference Detachment, P.O. Box 568337, Orlando, FL 32856-8337
Penn State Univ., University Park, PA 16802
Based on a previous design of a low-frequency, torsional shear wave transducer [A. K. Walden and T. R. Howarth, J. Acoust. Soc. Am. 91, 2463 (1992)], an analytical model is proposed to predict the radiated acoustic field. The stress and displacement fields produced by the S-wave source are analyzed with the appropriate boundary conditions. Then the continuity condition of the field (elastic wave equation) is employed to investigate the propagating subfields in the surrounding elastic/viscoelastic medium. The transducer studied is a cylindrical-type torsional vibrator. Therefore, it generates both horizontal and vertical radiation patterns. Computed, as well as measured results, of the acoustic response are presented for various couplings of different viscoelastic media with both the bimorph and torsional shear wave transducer designs. These results are useful for an optimal shear wave transducer design in the applications of ocean geoacoustics.