A transducer is constructed of a cylindrical shell and at least one pair of piezoelectric sections. Each member of the pair of piezoelectric sections is rigidly bonded to the wall of the cylinder, in a position diametrically opposed from the other member of the pair. Operation as an acoustic source transducer is accomplished by electrically energizing each piezoelectric section in such a manner as to cause the piezelectric sections to elongate and contract, respectively out of phase with one another, along the cylinder length. This causes flexural bending of the cylinder, with the bending being asymmetrical with respect to the cylinder axis. When one pair of piezoelectric sections is used in this manner, the transducer approximates an acoustic dipole radiator, and if more than one pair is used, the transducer can be used to approximate higher order polarized acoustic radiators. Various embodiments of the invention are particularly useful as either an acoustical source or detector in liquid-filled boreholes for geophysical application.
Thomas E. Owen