Discuss the implications of multi-mode propagation for the choice of a reference wavenumber, particularly in lossy environments with mode stripping.
Rayleigh’s principle for one-way wave propagation asserts that the average kinetic energy in the wave must be equal to the average potential energy, i.e., Here, u is the horizontal particle velocity, v the vertical particle velocity, and p the pressure. This energy conservation formula can be used to determine a “natural” reference wavenumber k0 for propagation […]
Derive the analytical solution for the equation below
Consider the one-dimensional wave equation subject to the boundary conditions You may assume the sound speed and density is constant for a. Show that the boundary condition at x = D represents the reflection from a plane interface separating two fluid media. b. Assume that [0; D] represents an acoustic medium with c = 1500m/s […]
Discuss the factors affecting the choice of element size for this problem.
Consider a fluid waveguide similar to the Pekeris waveguide, but with a continuously varying sound speed c.z/ in the water column. a. Using the simple linear elements formulate the FEM equations for the depth-separated wave equation. You may assume the sound speed to be linear (but not constant) within each element. b. Discuss the factors […]
Which array elements will record the head wave?
Assume you have a code for computing the transfer function p.r;z;!/ for the reflection which you want to use together with Fourier synthesis to model the transient response on a horizontal receiver array 100 m above the interface. The array has 11 elements at a spacing of 50 m, with the first element at r […]
Discuss the features of the beamformer response.
Assume you are using a long horizontal array for passively detecting a sound source in the ocean. The array characteristics are as follows: To estimate the source bearing in deep water it is often a good approximation to perform the beamforming assuming the source and the array are at equal depth in an infinite, homogeneous […]