Surface wave modelling and simulation for wave tanks and coastal areas

For testing ships and offshore structures in hydrodynamic laboratories, the sea and ocean states should be represented as realistic as possible in the wave tanks in which the scaled experiments are executed. To support efficient testing, accurate software that determines and translates the required wave maker motion into the downstream waves is very helpful. This paper describes an efficient hybrid spatial-spectral code that can deal with simulations above flat and varying bottom. The accuracy of the code will be illustrated by presenting comparisons of simulations with experimental data for various different type of non-breaking waves, from dispersive focussing waves to irregular wave fields with freak waves; the very broad-band spectra of such waves provide the main challeng

Propagation of wave groups over bathymetry using a variational Boussinesq model

Surface water waves propagating into shallow water are affected by the changes in the sea bed. Often, Boussinesq-type wave models are used to take these finite-depth effects into account. In Klopman et al. (2005), a variational method has been used to derive fully non-linear Boussinesq-type models from the full three-dimensional Hamiltonian structure. Th

A variational model for fully non-linear water waves of Boussinesq type

Using a variational principle and a parabolic approximation to the vertical structure of the velocity potential, the equations of motion for surface gravity waves over mildly sloping bathymetry are derived. No approximations are made concerning the non-linearity of the waves. The resulting model equations conserve mass, momentum and positive-definite energy. They are shown to have improved frequency-dispersion characteristics, as compared to classical Boussinesq-type of wave equations

A combination of Dirichlet to Neumann operators and perfectly matched layers as boundary conditions for optical finite element simulations

By combining Dirichlet to Neumann (DtN) operators and Perfectly Matched Layers (PML’s) as boundary conditions on a rectangular domain on which the Helmholtz equation is solved, the disadvantages of both methods are greatly diminished. Due to the DtN operators, light may be accurately fluxed into the domain, while the PML’s absorb light that is reflected from the corners of the domain when only DtN boundaries are used

Effect of a possible Anak Krakatau explosion in the Jakarta Bay

Plans to build a sea dike in the Jakarta Bay to solve the multiple water problems in the Jakarta area should take into account the possibility of tsunami waves from a possible future explosion of Anak Krakatau. To obtain a rough indication of the possible waves we took the waves caused by the 1883 explosion of the Krakatau as guidance. The inverse problem to determine a possible generation scenario that produces similar waves as in 1883 is considered here using a relatively simple phreato-magmatic explosion model. For the simulations we use a Finite Element implementation of a linear Variational Boussinesq model