##### Project name

Minimierung unerwünschter Wellenreflexionen an den Gebietsrändern in Strömungssimulationen mit freier Oberfläche basierend auf den Navier-Stokes Gleichungen

Minimizing undesired wave reflections at the domain boundaries in flow simulations with free-surface waves based on the Navier-Stokes equations

##### Project description

Wave reflections at the boundaries of the computational domain can cause significant errors in flow simulations, and must therefore be reduced. This can be achieved via forcing-zone-type approaches such as absorbing layers, sponge layers, damping zones, or relaxation zones. These approaches gradually force the solution in the vicinity of the boundary towards some prescribed reference solution. Forcing zones are versatile since they can be applied near both wave-generating and wave-absorbing boundaries and can be used for flows with superposed currents. However, the key problem is that forcing zones contain case-dependent parameters, such as the zone thickness or the source term magnitude.

In the first part of this project, an analytical approach was developed to optimally select these parameters. The project was successful and further details can be found under the following link.

For 3D-flow simulations, different `forcing zone arrangements' can be used, which differ in the choice of governing equations, to which the forcing is applied, the choice of domain boundaries, to which forcing zones are attached, and the choice of reference solution, towards which the solution is forced. Two common examples are shown below.

The first aim of this project is to assess the aforementioned influences via 3D-flow simulations with strongly reflecting bodies subjected to long-crested free-surface waves. This is important for engineering practice since some forcing zone arrangements were shown to produce flow disturbances, which can radiate undesired waves into the solution domain.

The second aim of this project is to devise an approach to enable flow simulations of short-crested waves, to model realistic sea states with waves traveling in different directions. For this, the forcing zone arrangement for long-crested free-surface waves from the previous part of the project will be extended to short-crested waves.

##### Funding

The project is funded by the Deutsche Forschungsgemeinschaft (DFG) with grant AB 112/11-2.

##### Personnel

Prof. Dr.-Ing. Moustafa Abdel-Maksoud

M.Sc. Robinson Peric