Analysing numerical overtopping predictions for armoured hydraulic structures using generated rubble rock and porous modelling techniques

This work is concerned with the numerical modelling of overtopping over hydraulic structures that are constructed with rubble rock. Two-dimensional CFD simulations employing porous modelling techniques in order to account for the resistance imposed by the rubble rock on the wave run-up show a high sensitivity to turbulence modelling. Furthermore, when considering thin armour layers, the assumption of a homogeneous porous zone loses its validity. Therefore, a method is developed to generate rubble rock geometries which are subsequently placed in a layer packing using discrete element modelling. These geometries are then used to model the flow through the armour rock explicitly. Although initial results seem promising, stability issues due to high Courant numbers limited the required simulation time for a quantitative comparison to the porous modelling technique.