The 12th International Conference on Hydrodynamics
18 – 23 september 2016, Egmond aan Zee, The Netherlands
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GENERATING AND ABSORBING BOUNDARY CONDITIONS FOR COMBINED WAVE-CURRENT SIMULATIONS


Go-down ichd2016 Tracking Number 53

Presentation:
Session: Linear and non-linear waves I
Room: Room 2
Session start: 14:00 Tue 20 Sep 2016

Xing Chang   x.chang@tudelft.nl
Affifliation: PhD Candidate

Ido Akkerman   I.Akkerman@tudelft.nl
Affifliation: Assistant Professor

Rene Huijsmans   R.H.M.Huijsmans@tudelft.nl
Affifliation: Professor

Arthur Veldman   a.e.p.veldman@rug.nl
Affifliation: Professor


Topics: - Linear and non-linear waves and current, - Computational fluid dynamics

Abstract:

The CFD simulation tool ComFLOW is extended to investigate the characteristics of wave motions in the presence of steady uniform currents. Initially, the inflow boundary is the superposition of waves and current. Effect of the latter on the former is resolved by solving Navier-Stokes equations within the domain as a next step. A Generating and Absorbing Boundary Condition (GABC) with currents is introduced that allows the simulation of a combined wave-current environment in truncated domain. This GABC is characterized by a rational function approximation of dispersion relation, based on Sommerfeld condition and irrotational wave model. The artificial boundaries where GABC with current is applied are transparent to incoming and outgoing waves and currents simultaneously. The absorption properties of the GABC for various waves and currents are analysed. The temporal and spatial differences of free surface elevation between the small domain and large domain turn out to be small, i.e. the GABC prevents the reflection from the boundaries well. The large domain here is arranged in such a way that the reflected waves and currents will not reach the outflow boundary of the small domain within the simulation time. The behaviour of GABC in 3D domain is also investigated, where waves and currents are traveling under an angle of incidence colinearly.