APPLICATION OF A TRIDIMENSIONAL NON LINEAR NUMERICAL MODEL TO SEA WAVES OVER SUBMERGED TRAPEZOIDAL BREAKWATERS

The performance of the three-dimensional non-linear Navier-Stokes model, FLUINCO, in the simulation of wave propagation on variable depth is here analyzed. The numerical model is based on the integration of the Navier-Stokes equations (Teixeira(46)), which are discretized in time and space by two steps semi-implicit Taylor-Galerkin scheme that uses linear tetrahedra. An arbitrary lagrangean eulerian formulation that is compatible with the free surface movement is adopted. First, the code is tested for the case of a monochromatic wave propagation in a channel and the numerical results (pressure and velocity fields) are compared with the theoretical solutions. Then, the model is successively applied to problems involving the trapezoidal breakwaters. Different breakwater profiles were considered: all have the same slope of 1:20 on the sea side, but the breakwaters have slopes of 1:10 (breakwater profile was studied experimentally by Dingemans(10)), 45 degrees and 90 degrees on the lee side. In addition to the free surface elevation values at several points in the domain, pressure and velocity fields are also presented. Whereas in the first case, with downslope of 1:10, the flow shows no separation vortices formation, the same does not apply to the other two cases, where the presence of vortices near the junction of the platform with the downstream ramp is observed. The results show the ability of the model to deal with problems in which the vertical movement is significant, including phenomena such as flow separation and vortex formation.