MATLAB Implementation for Ocean Acoustic Propagation Calculation

MATLAB Implementation for Ocean Acoustic Propagation Calculation

In the field of ocean acoustics, acoustic propagation calculation represents a core problem involving various numerical methods such as FFP (Fast Field Program), PE (Parabolic Equation), normal mode methods, and ray tracing approaches. These methods each have distinct advantages and limitations in different application scenarios. MATLAB, with its powerful numerical computation capabilities, serves as an ideal platform for implementing these algorithms.

FFP Method (Fast Field Program) The FFP method solves the wave equation using Fast Fourier Transform (FFT), making it suitable for sound field calculations in horizontally stratified media. In MATLAB implementation, the built-in FFT functions enable efficient transformation from frequency domain to spatial domain for computing sound field distributions. The FFP method offers rapid computation speed but has limited accuracy in complex marine environments with strong three-dimensional variations.

PE Method (Parabolic Equation) The PE method simplifies three-dimensional problems into two-dimensional ones by approximating the wave equation, making it appropriate for long-range acoustic propagation simulations. MATLAB's matrix operation capabilities are particularly well-suited for solving the discrete forms of parabolic equations, typically employing numerical schemes like Crank-Nicolson for iterative calculations. The PE method performs well in both deep and shallow water environments but requires substantial computational resources.

Normal Mode Method The normal mode method represents the sound field as a superposition of series of modes by solving eigenvalue problems. MATLAB's linear algebra tools (such as the `eig` function) can efficiently compute eigenvalues and eigenfunctions. This method is suitable for low-frequency acoustic propagation but becomes computationally expensive at high frequencies or in complex environments.

Ray Tracing Method Based on geometric acoustics approximation, the ray tracing method calculates sound fields by tracking acoustic ray paths. MATLAB's numerical integration and optimization functions (like `ode45`) can be employed to solve ray trajectory equations. The ray method is particularly effective for high-frequency acoustic propagation but ignores wave effects, leading to reduced accuracy in caustic regions and other special areas.

Summary MATLAB provides a flexible and efficient implementation platform for ocean acoustic propagation calculations. FFP is suitable for rapid computations, PE excels in long-distance propagation scenarios, normal mode methods demonstrate excellent performance in low-frequency applications, while ray tracing methods offer advantages in high-frequency analysis. Depending on specific problem requirements, appropriate numerical methods can be selected or combined for comprehensive simulations.