Testing and verification of a scale-model acoustic propagation system

Area of Science:

• Oceanography
• Acoustics
• Wave Propagation

Background:

• Underwater acoustic propagation is crucial for sonar and communication.
• Accurate experimental data is needed to validate numerical models.
• Scale-model experiments offer a controlled environment for studying complex acoustic phenomena.

Purpose of the Study:

• To design and operate a novel measurement apparatus for scale-model underwater acoustic propagation experiments.
• To demonstrate the apparatus's capability in a simple, primarily two-dimensional (2D) acoustic propagation waveguide.
• To compare experimental results with two-dimensional (2D) and three-dimensional (3D) numerical model predictions.

Main Methods:

• Utilized a computer-controlled positioning system for a receiving transducer above a scale-model bathymetry.
• Employed a stationary source transducer emitting broadband pulsed waveforms.
• Applied a simulated annealing inversion method to infer waveguide parameters for model validation.

Main Results:

• Experimental data acquired for a 2.133m x 1.219m bathymetric section with a 10° wedge slope.
• Beamformed results revealed strong in-plane arrivals and weaker diffracted/refracted arrivals.
• Inferred waveguide parameters were used to simulate measured acoustic data using 2D and 3D models.

Conclusions:

• The developed apparatus is capable of conducting accurate scale-model underwater acoustic propagation experiments.
• Experimental results align well with predictions from both 2D and 3D numerical models.
• The study validates the use of scale-model experiments for understanding complex acoustic wave phenomena.