Specific acoustic impedance of the ultrasonic field by the square flat transducers

Sound pressure, particle velocity, and specific acoustic impedance are investigated, using the case where square flat transducers are tilted from a parallel condition. Specific acoustic impedance is a quotient of sound pressure by particle velocity. Particle velocity is computed by numerical quadruple integration with Huygens’s principle, and compared with that of the plane wave. The ratio of the half side length (a) of the square flat transducer to the wavelength (λ) of the ultrasonic wave is set at 2.5, and the distance between the transducers is set at 5a or 10a. The feature of the phase delay leap of the specific acoustic impedance on the central axis of the circular flat transducer does not appear for the square case.