Numerical simulations of wave–current flow in an ocean basin (original) (raw)

Wave–current interaction: Effect on the wave field in a semi-enclosed basin

Ocean Modelling, 2013

The effect on waves of the Wave-Current Interaction (WCI) process in the semi-enclosed Gulf of Venice (northern region of the Adriatic Sea) was investigated using the Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modeling system. COAWST relies on the ocean model ROMS (Regional Ocean Modeling System), the wave model SWAN (Simulating WAves Nearshore), and the CSTMS (Community Sediment Transport Modeling System) routines. The two-way data transfer between circulation and wave models was synchronous via MCT (Model Coupling Toolkit), with ROMS providing: current field, free surface elevation, and bathymetry to SWAN. For coupling, the 3-D current profiles were averaged using a formulation which integrated the near-surface velocity over a depth controlled by the spectral mean wavenumber. COAWST system was implemented on a parent grid (with horizontal resolution of 2.0 km) covering the whole Adriatic Sea with one-way nesting to a child grid resolving the northern area (Gulf of Venice) at a resolution of 0.5 km. The meteorological forcings provided by the operational meteorological model COSMO-I7 (a mesoscale model developed in the framework of the COSMO Consortium) were used to drive the modeling system in the period bracketing September 2010-August 2011. The adopted winds and the simulated waves were compared with observations at the CNR-ISMAR Acqua Alta oceanographic tower, located off the Venice littoral. Wave heights and sea surface winds were also compared with satellite-derived data. The analysis of WCI was performed on the child grid over the winter season (January-March 2011) with particular focus on the waves generated by prevailing and dominant winds blowing on the Adriatic Sea: Bora and Sirocco. Due to the variable wind direction with respect to the ocean current direction different effects on WCI were depicted, showing that within the northern Adriatic Sea the ocean-wave interactions are strongly dependent on the wind forcing direction. Further investigations reveal that, when applied to intense storms, the effect of coupling on waves results in variations of significant wave height up to 0.6 m, with some areas experiencing significant increase/decrease of wave spectral energy for opposite/following currents respectively.

Hydrodynamic model with wave–current interaction in coastal regions

Estuarine, Coastal and Shelf Science, 2004

The effects of wave-current interaction on the hydrodynamics in coastal regions are investigated. A modified Grant-Madsen analytical model is incorporated into the Princeton Ocean Model (POM) to describe the wave-current interaction. The model is applied to the Singapore Straits for the prediction of tide and wind driven circulation. The simulation results confirm that high shear velocity within the wave bottom boundary layer produces high levels of turbulence intensities. The strong turbulence intensities within the thin wave bottom boundary layer in turn affect the currents through increased bottom resistance.

A CFD model application to analyze the vertical structure of flow in the wave-current environment

2013

The nearshore hydrodynamics and coastal circulation result from a variety of phenomena involving complex physical interactions with different scales (large scale circulation currents, tidal effects, waves, wind action, etc.). Among these interactions, we focus on the interaction between waves and currents, especially when the current presents a strong shear over the water depth. In the present work, the evaluation and analysis of wave-current interactions is made through numerical simulations based on Reynolds Averaged Navier-Stokes (RANS) equations, applied to the modelling of the complete flow motion, namely waves and currents simultaneously (i.e. without decoupling the two phenomena). The advanced CFD solver Code_Saturne (ARCHAMBEAU et al., 2004) is used for this purpose. Numerical results are compared with experimental data from UMEYAMA (2005). Four different wave heights and wave periods are tested for each case: (i) waves only, (ii) waves following current and (iii) waves oppo...

Simulation of ocean waves in coastal areas using the shallow-water equation

Journal of Physics: Conference Series, 2019

This study simulates shallow water waves using the Navier-Stokes equation. This simulation uses the MatLab application, especially Quickersim with 2-dimensional output. Mesh in simulation is made using Gmsh. Research about shallow water has an essential role in studying the characteristics of ocean waves. The depth of the sea influences this characteristic. Data obtained from this simulation is in the wave height and velocity positions at any time. The limitations in the data collected are not comparable with the experimental results because there are no experimental Navier-Stokes simulations, but these simulation results have shown the phenomenon of seawater movement. In future work, the results of this study can be used to analyse its application in tsunami waves.

Numerical Modeling Of Waves And Currents By Using A Hydro-Sedimentary Model

2016

Over recent years much progress has been achieved in the fields of numerical modeling shoreline processes: waves, currents, waves and current. However, there are still some problems in the existing models to link the on the first, the hydrodynamics of waves and currents and secondly, the sediment transport processes and due to the variability in time, space and interaction and the simultaneous action of wave-current near the shore. This paper is the establishment of a numerical modeling to forecast the sediment transport from development scenarios of harbor structure. It is established on the basis of a numerical simulation of a water-sediment model via a 2D model using a set of codes calculation MIKE 21-DHI software. This is to examine the effect of the sediment transport drivers following the dominant incident wave in the direction to pass input harbor work under different variants planning studies to find the technical and economic limitations to the sediment transport and protec...

A numerical model for wave-current interaction at the scale of marine engineering

Journal of Operational Oceanography, 2016

In the present paper a numerical method for marine and coastal hydrodynamics is presented. It aims at developing a formulation for the complete wave-current coupling in the time domain. In this framework, both waves and currents are handled by complete Navier-Stokes equations. Indeed, waves are modified by currents and interaction with structures, the flow is forced by waves and structures as well. The numerical solution for fully 3D equations is outlined, showing that the proposed procedure is a revisited version of the fractional step method, i.e. the free surface fractional step method. Some numerical test cases in simple 2D geometries (vertical direction vs direction of wave propagation) are shown.

On the modeling of wave–current interaction using the elliptic mild-slope wave equation

Ocean Engineering, 2005

Methods to incorporate the effect of ambient currents in the prediction of nearshore wave transformation are developed. This is accomplished through the construction of a finite-element coastal/harbor wave model based on an extended mild-slope wave-current equation that includes wave breaking. Improved boundary conditions are used to provide more accurate forcing and to minimize spurious wave reflections from the boundaries. Multiple nonlinear mechanisms, appearing both in the governing equations and in the boundary conditions, are handled successfully and efficiently with iterative techniques. The methods are tested against results from other types of models based on parabolic approximations or Boussinesq equations for three wave-current problems of common interest and varying complexity. While indicating good agreement in general, the analysis also highlights the limitations of parabolic approximation models in case of strong local currents and velocity shear. We also consider the harbor engineering problem pertaining to waves approaching an inlet with a jettied entrance, where wavecurrent interaction can create a complex wave pattern that adversely affects small craft navigation and causes scouring. The role of ebb and flood currents on wave transformation and on breaking in the vicinity of the inlet is investigated using the model in conjunction with hydraulic laboratory data. It is found that although the ebb currents cause larger waves outside the inlet, much of the wave energy is soon dissipated due to breaking; during the flood tide, in contrast, more wave energy can penetrate into the inlet throat. q Ocean Engineering 32 (2005) 2135-2164 www.elsevier.com/locate/oceaneng 0029-8018/$ -see front matter q

A fully coupled method for simulation of wave-current-seabed systems

Communications in Nonlinear Science and Numerical Simulation, 2013

Coastal flow involves surface wave propagation, current circulation, and seabed evolution, and its prediction remains challenging when they strongly interact with each other, especially during extreme events such as tsunami and storm surge. We propose a fully coupled method to simulate motion of wave-current-seabed systems and associated multiphysics phenomena. The wave action equation, the shallow water equations, and the Exner equation are respectively used for wave, current, and seabed morphology, and the discretization is based on a second-order, flux-limiter, finite difference scheme previously developed for current-seabed systems. The proposed method is tested with analytical solutions, laboratory measurements, and numerical solutions obtained with other schemes. Its advantages are demonstrated in capturing interplay among wave, current, and seabed; it has the capability of first-order upwind schemes to suppress artificial oscillations as well as the accuracy of second-order schemes in resolving flow structures.