Including the effect of depth-uniform ambient currents on waves in a non-hydrostatic wave-flow model

Rijnsdorp, D.P.; van Rooijen, Arnold; Reniers, A.J.H.M.; Tissier, M.F.S.; de Wit, F.P.; Zijlema, Marcel

doi:10.1016/j.coastaleng.2023.104420

Including the effect of depth-uniform ambient currents on waves in a non-hydrostatic wave-flow model

Title

Including the effect of depth-uniform ambient currents on waves in a non-hydrostatic wave-flow model

Author

Rijnsdorp, D.P. (TU Delft Environmental Fluid Mechanics)
van Rooijen, Arnold (University of Western Australia)
Reniers, A.J.H.M. (TU Delft Environmental Fluid Mechanics)
Tissier, M.F.S. (TU Delft Environmental Fluid Mechanics)
de Wit, F.P. (TU Delft Environmental Fluid Mechanics; Svašek Hydraulics)
Zijlema, Marcel (TU Delft Environmental Fluid Mechanics)

Date

2023

Abstract

Currents can affect the evolution of waves in nearshore regions through altering their wavenumber and amplitude. Including the effect of ambient currents (e.g., tidal and wind-driven) on waves in phase-resolving wave models is not straightforward as it requires appropriate boundary conditions in combination with a large domain size and long simulation duration. In this paper, we extended the non-hydrostatic wave-flow model SWASH with additional terms that account for the influence of a depth-uniform ambient current on the wave dynamics, in which the current field can be taken from an external source (e.g., from observations or a circulation model). We verified the model ability by comparing predictions to results from linear theory, laboratory experiments and a spectral wave model that accounts for wave interference effects. With this extension, the model was able to account for current-induced changes to the wave field (i.e., changes to the wave amplitude, length and direction) due to following and opposing currents, and two classical examples of sheared currents (a jet-like current and vortex ring). Furthermore, the model captured the wave dynamics in the presence of strong opposing currents. This includes reflections of relatively small amplitude waves at the theoretical blocking point, and transmission of breaking waves beyond the theoretical blocking point for larger wave amplitudes. The proposed model extension allows phase-resolving models to more accurately and efficiently simulate the wave dynamics in coastal regions with tidal and/or wind-driven flows.

Subject

Non-hydrostatic
SWASH
Wave–current interactions

To reference this document use:

http://resolver.tudelft.nl/uuid:f567f476-0545-4e94-bbd3-c40cdcbdc212

DOI

https://doi.org/10.1016/j.coastaleng.2023.104420

ISSN

0378-3839

Source

Coastal Engineering, 187

Part of collection

Institutional Repository