HR: 0800h
AN: OS11A-0501    [Abstracts]
TI: A Boussinesq-Type Wave Model as a Wave Driver for a Morphodynamic Model
AU: * Wenneker, I
EM: Ivo.Wenneker@wldelft.nl
AF: WL | Delft Hydraulics, P.O. Box 177, Delft, 2600 MH Netherlands
AU: Borsboom, M
EM: Mart.Borsboom@wldelft.nl
AF: WL | Delft Hydraulics, P.O. Box 177, Delft, 2600 MH Netherlands
AU: Dongeren, A v
EM: Ap.vanDongeren@wldelft.nl
AF: WL | Delft Hydraulics, P.O. Box 177, Delft, 2600 MH Netherlands
AU: Roelvink, D
AF: WL | Delft Hydraulics, P.O. Box 177, Delft, 2600 MH Netherlands
AB: The current generation of operational morphodynamic models is based on the short-wave averaged depth-integrated Reynolds equations. Because the short waves are averaged out, a separate module, the wave driver, is needed to provide the wave-depentdent forcing in the momentum equations. Most operational models use a steady wave driver based on linear theory, which means that certain aspects relevant to the sediment transport formulations need to be parametrized. We will present the results of using the phase-resolving Boussinesq-type wave model TRITON as a wave driver, which computes the wave forces. These are transferred to the short-wave averaged free-surface model DELFT3D for the computation of flow, sediment transport, and morphological changes. In this way, the time-integrated effects of intra-wave properties such as individual wave height transformation (including breaking), wave skewness and wave asymmetry, and drift velocities are communicated online with DELFT3D. The changes in bathymetry predicted by DELFT3D are transferred back to TRITON to include this effect in the simulation of the wave dynamics. In particular, we will discuss the online separation of waves into long and short waves (this must be done in time domain to get the time-integrated effects of the intra-wave properties), and reconstruction of the velocity over the vertical coordinate. Validation of the wave part of the methodology is done by comparison with high-resolution wave flume experiments by Boers (1996). The combined strength of both models will improve the prediction capabilities for nearshore morphodynamics in response to wind wave forcing on the time scale of a storm event. This work is funded by the U.S. Office of Naval Research under contract N00014-02-C0075.
DE: 4546 Nearshore processes
DE: 4558 Sediment transport
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting