Session: 08-02-01 Free Surface Flows

Paper Number: 127429

127429 - A Shock-Absorbing Non-Hydrostatic Navier-Stokes Solver on σ-Grids for Wave Modeling Over Irregular Topography 

Recently, a variety of Computational Fluid Dynamics (CFD) based Numerical Wave Tanks (NWT) have been introduced that resolve the wave propagation and the associated wave hydrodynamics in great detail. For a range of ocean and coastal engineering scenarios, a faster solution of nonlinear wave propagation is more desirable. High-order spectral (HOS) wave models and fully nonlinear potential flow (FNPF) models are possible candidates for fast wave propagation simulations in deep water. For example, designing offshore wind substructures often requires the identification of significant wave events, currents and sediment transport processes combined. The dynamics of each phenomenon are strongly correlated and contribute to the investigated situation such as their impact on the offshore structures. A potential flow model is very capable to solve pure wave propagation problems. For wave-current as well as sediment processes, viscous flow that can include the effects of turbulence is more suitable. This paper presents a three-dimensional non-hydrostatic model deployed on a moving σ-coordinate grid: REEF3D::NHFLOW. Solving the non-hydrostatic Navier-Stokes equations maintains a detailed result. The surface and bottom following grid enables the use of grid refinement near the water surface or the bottom topography while keeping the computational effort low. REEF3D::NHFLOW is developed for complex free surface flows in the framework of the open-source hydrodynamics model REEF3D and is fully parallelized following the domain decomposition strategy and the MPI communication between the individual processors. The current paper demonstrates the capabilities of the new efficient one-phase flow model by using a free surface and bottom following σ-grid approach.

Presenting Author: Hans Bihs NTNU Trondheim

Presenting Author Biography: since 2006 at NTNU

Authors:

Hans Bihs NTNU Trondheim
Ronja Ehlers NTNU Trondheim
Widar Weizhi Wang NTNU Trondheim