29,358 research outputs found
Time-Reversal of Nonlinear Waves - Applicability and Limitations
Time-reversal (TR) refocusing of waves is one of fundamental principles in
wave physics. Using the TR approach, "Time-reversal mirrors" can physically
create a time-reversed wave that exactly refocus back, in space and time, to
its original source regardless of the complexity of the medium as if time were
going backwards. Lately, laboratory experiments proved that this approach can
be applied not only in acoustics and electromagnetism but also in the field of
linear and nonlinear water waves. Studying the range of validity and
limitations of the TR approach may determine and quantify its range of
applicability in hydrodynamics. In this context, we report a numerical study of
hydrodynamic TR using a uni-directional numerical wave tank, implemented by the
nonlinear high-order spectral method, known to accurately model the physical
processes at play, beyond physical laboratory restrictions. The applicability
of the TR approach is assessed over a variety of hydrodynamic localized and
pulsating structures' configurations, pointing out the importance of high-order
dispersive and particularly nonlinear effects in the refocusing of hydrodynamic
stationary envelope solitons and breathers. We expect that the results may
motivate similar experiments in other nonlinear dispersive media and encourage
several applications with particular emphasis on the field of ocean
engineering.Comment: 14 pages, 17 figures ; accepted for publication in Phys. Rev. Fluid
Tsunami generation by ocean floor rupture front propagation: Hamiltonian description
The Hamiltonian method is applied to the problem of tsunami generation caused by a propagating rupture front and deformation of the ocean floor. The method establishes an alternative framework for analyzing the tsunami generation process and produces analytical expressions for the power and directivity of tsunami radiation (in the far-field) for two illustrative cases, with constant and gradually varying speeds of rupture front propagation
Wave modelling - the state of the art
This paper is the product of the wave modelling community and it tries to make a picture of the present situation in this branch of science, exploring the previous and the most recent results and looking ahead towards the solution of the problems we presently face. Both theory and applications are considered.
The many faces of the subject imply separate discussions. This is reflected into the single sections, seven of them, each dealing with a specific topic, the whole providing a broad and solid overview of the present state of the art. After an introduction framing the problem and the approach we followed, we deal in sequence with the following subjects: (Section) 2, generation by wind; 3, nonlinear interactions in deep water; 4, white-capping dissipation; 5, nonlinear interactions in shallow water; 6, dissipation at the sea bottom; 7, wave propagation; 8, numerics. The two final sections, 9 and 10, summarize the present situation from a general point of view and try to look at the future developments
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