title: Testing and verification of a scale-model acoustic propagation system.
abstract: This paper discusses the design and operation of a measurement apparatus used to conduct scale-model underwater acoustic propagation experiments, presents experimental results for an idealized waveguide, and compares the measured results to data generated by two-dimensional (2D) and three-dimensional (3D) numerical models. The main objective of this paper is to demonstrate the capability of the apparatus for a simple waveguide that primarily exhibits 2D acoustic propagation. The apparatus contains a computer-controlled positioning system that accurately moves a receiving transducer in the water layer above a scale-model bathymetry while a stationary source transducer emits broadband pulsed waveforms. Experimental results are shown for a 2.133 m × 1.219 m bathymetric part possessing a flat-bottom bathymetry with a translationally invariant wedge of 10° slope along one edge. Beamformed results from a synthetic horizontal line array indicate the presence of strong in-plane arrivals along with weaker diffracted and horizontally refracted arrivals. A simulated annealing inversion method is applied to infer values for five waveguide parameters with the largest measurement uncertainty. The inferred values are then used in a 2D method of images model and a 3D adiabatic normal-mode model to simulate the measured acoustic data.
authors.affiliation: Applied Research Laboratories, The University of Texas at Austin, P.O. Box 8029, Austin, Texas 78713-8029, USA.
authors.forename: Jason D
authors.initials: JD
authors.lastname: Sagers
authors.affiliation: Applied Research Laboratories, The University of Texas at Austin, P.O. Box 8029, Austin, Texas 78713-8029, USA.
authors.forename: Megan S
authors.initials: MS
authors.lastname: Ballard