This report concerns the validation of surface velocity estimated from satellite images. The estimation is obtained with a dynamic model based on shallow-water equations. We first compare the stationary assumption to the shallow-water heuristics to justify our choice. Second, we quantify the quality of the estimation by measuring the misfit between the model output and the altimetry measures. E...

The shallow-water model is used as a testbench for understanding many fundamental dynamical problems (e.g. certain wave–mean interaction problems). One sometimes wants to allow large-amplitude gravity waves to propagate significant distances in such models without forming shocks. This paper presents a simple, and apparently unique, modification of the standard shallow-water model that prevents ...

The shallow water magnetohydrodynamic system describes the thin layer evolution of the solar tachocline. It is obtained from the three dimensional incompressible magnetohydrodynamic system similarly as the classical shallow water system is obtained from the incompressible NavierStokes equations. The system is hyperbolic and has two additional waves with respect to the shallow water system, the ...

A general method for the derivation of asymptotic nonlinear shallow water and deep water models is presented. Starting from a general dimensionless version of the water-wave equations, we reduce the problem to a system of two equations on the surface elevation and the velocity potential at the free surface. These equations involve a Dirichlet-Neumann operator and we show that all the asymptotic...

Recent progress in the development of a physics-based numerical propagation model for the virtual transmission of acoustic communication signals in shallow water is presented. The ultimate objective is to provide for the prediction of the output of the quadrature detector (QD, an analog of the discrete Fourier transform) in a time-variant, doubly dispersive, shallow-water channel. Current model...

A new grid generation method for the computation of shallow water ̄ows is presented. The procedure, based on the use of cut cells on a Cartesian background mesh, can cope with shallow water problems having arbitrarily complex geometries. Although the method provides a fully boundary-®tted capability, no mesh generation in the conventional sense is required. Solid regions are simply cut out of a...

For the simulation of tsunamis, the hydrostatic shallow water equations have established as a sound mathematical basis. However, due to the hydrostatic assumption, not all relevant physical effects—especially in coastal areas—can be modelled accurately. In this paper, we therefore show how to extend the PDE-framemwork sam(oa)2 towards modified non-hydrostatic shallow water equations. We use the...

A simple and accurate projection finite volume method is developed for solving shallow water equations in two space dimensions. The proposed approach belongs to the class of fractional-step procedures where the numerical fluxes are reconstructed using the method of characteristics, while an Eulerian method is used to discretize the conservation equations in a finite volume framework. The method...

Four different water sources (irrigation canals, small reservoirs, shallow wells, and tubewells), used for domestic purposes, in an irrigated area in southern Sri Lanka, were tested for Giardia spp. cysts and Cryptosporidium spp. oocysts. Identification of these parasites in water sources is important as these are increasingly recognized as causative agents of waterborne diarrhoeal disease. All...

The long term goals are to (1) understand the role of wave-induced bubbles in the upper ocean boundary layer on the performance of underwater communications systems and ambient noise generation, (2) study the implications of focusing by surface gravity waves on Doppler sonar and acoustic communications systems in shallow and very shallow water, and (3) study the performance of acoustic vector s...