Nonlinear Interaction of Ultrasonic Beams in Air

Parametric arrays are widely used in underwater environment. Recently, efforts have been made to apply parametric radiation to audio sound reproduction in air. However, some presumptions used in underwater acoustic analyses are not applicable in air, especially for sources with small sizes. A possible solution is to numerically solve the KZK equation, which is the well accepted “exact” model equation for directional acoustic beams. In this paper, a small plane circular piston source is considered and a finite difference technique is used to numerically solve the KZK equation. Experiments are also performed. It is shown that numerical results are in good agreement with the experimental measurements.