Narrow Results

A set of fully nonlinear Boussinessq-type equations with improved linear and nonlinear properties is considered for wave–current interaction analysis. These phase-resolving equations are so that the highest order of the derivatives is three. We implement a new source function for the wave–current generation within the domain, which allows to generate a wide range of wave–current conditions. The set of equations is solved using a fourth order explicit numerical scheme which semi-discretizes the equations in space and then integrates in time using an explicit Runge–Kutta scheme. A novel treatment of the boundaries, which uses radiative boundary conditions for the current and damps the waves, is used to avoid boundary reflections. Several validation tests are presented to demonstrate the capabilities of the new model equations for wave–current interaction.

To better understand the physical processes involved in the wave–seabed–pipeline interactions (WSPI), a three-dimensional numerical model for the wave-induced soil response around an offshore pipeline is proposed in this paper. Seabed instability around an offshore pipeline is one of the key factors that need to be considered by coastal engineers in the design of offshore infrastructures. Most previous investigations into the problem of WSPI have only considered wave conditions and have not included currents, despite the co-existence of waves and currents in natural ocean environments. Unlike previous studies, currents are included in the present study for the numerical modeling of WSPI, using an integrated FVM model, in which the volume-averaged Reynolds-averaged Navier–Stokes (VARANS) equation is used to solve the mean fluid field, while Biot’s consolidation equation is used to describe the solid–pore fluid interaction in the porous medium. Numerical examples demonstrate a significant influence of ocean current direction and angle on the wave-induced pore pressures and the resultant seabed liquefaction around the pipeline, which cannot be observed in two-dimensional (2D) numerical simulation.

This paper studies on interactions between morphological changes and wave and current fields around the Tenryu River mouth during a severe storm. Installing six cameras, authors successfully captured collapse of sand bar around the Tenryu River mouth when typhoon T0704 hit the Pacific Coast of Japan in July 2007. Obtained images were analyzed based on several image processing techniques and, coupled with the other hydrodynamic data, showed clear evidence for interactive features of bathymetry changes and surrounding wave and current fields. Finally, a numerical model based on depth-integrated non-linear shallow water equations and energy balance equations were applied to the observed conditions and it was found that topography changes during the storm was one of the most essential factors that determine the characteristics of surrounding wave and current fields.