Scattering Theory of Gravity-Flexural Waves of Floating Plates on Water

Mohamed Farhat, et al., "Scattering Theory of Gravity-Flexural Waves of Floating Plates on Water". arXiv preprint arXiv:1901.09733. Phys. Rev. B 101,  2019, 014307.

We combine theories of scattering for linearized water waves and flexural waves in thin plates to characterize and achieve control of water wave scattering using floating plates. This requires manipulating a sixth-order partial differential equation with appropriate boundary conditions of the velocity potential. Making use of multipole expansions, we reduce the scattering problem to a linear algebraic system. The response of a floating plate in the quasistatic limit simplifies, considering a distinct behavior for water and flexural waves. Unlike similar studies in electromagnetics and acoustics, scattering of gravity-flexural waves is dominated by the zeroth-order multipole term and this results in non-vanishing scattering cross-section also in the zero-frequency limit. Potential applications lie in floating structures manipulating ocean waves.