Ultrasonic wave propagation through aberrating layers: experimental verification of the conjugate gradient Rayleigh method

The Conjugate Gradient Rayleigh method for the calculation of acoustic reflection and transmission at a rough interface between two media was experimentally verified. The method is based on a continuous version of the conjugate gradient technique and plane-wave expansions. We measured the beam profiles of a nonfocused linear array transducer distorted by propagation through an aberrating interface. The directivity of the hydrophone was compensated for by means of spatial deconvolution. Sinusoidal, cylindrical aberrators were made of a water-based gelatine material. The measurements were compared with 2- and 3-D simulations. The measured and simulated beam profiles are in good agreement, as shown by the root-mean-square difference.