Numerical Analysis of the Semisubmersible Using Generating-Absorbing Boundary Conditions

The present work tests the performance of an efficient boundary condition called generating-absorbing boundary condition (GABC) for free-surface waves and studies its effect on computational efficiency. Numerical simulations of a semisubmersible substructure are performed with two different boundary conditions with low spurious reflection: relaxation zone and GABC. These simulations are conducted for regular sea states in OpenFOAM and have been validated using experimental data obtained from the OC6 campaign. The numerical results with relaxation zone boundary condition and GABC agreed well with the experimental results. Using GABC also resulted in an almost 15% reduction in computational time compared to the conventional approaches.