FIG. 2.

Simulated time-harmonic pressure field for a 5λ wide and 7.5λ high rectangular source. The wavelength of the acoustic excitation is represented by λ, so the element half width is 2.5λ, and the aspect ratio is b/a = 1.5. This simulated pressure distribution, which serves as the reference for subsequent error calculations, is obtained when Eq. (2) is evaluated with 200 000-point Gauss quadrature for each of the subelements and then superposed according to Eq. (3).