Propagation over a rigid sea ridge using a three-dimensional finite element model

A three-dimensional finite element model is developed to describe propagation over a rigid underwater sea ridge. Finite element models are attractive benchmark solutions since they include all orders of scattering as well as refraction. In this case, the model is calculated using an out-of-plane wavenumber decomposition technique which utilizes a series of two-dimensional models to calculate a fully three-dimensional model in longitudinally invariant environments. [Isakson et al., J. Acoust. Soc. Am. Express Letters, 136:EL206-211, 2014.] The time-harmonic model is then extended to the time domain via Fourier synthesis in order to more fully understand the dynamics of modal refraction and propagation over the ridge. The model is compared with coupled mode solutions from the University of Rhode Island. [Work supported by ONR, Ocean Acoustics.]