In the three parts of each forces, only one is non equal to zero. For the horizontal strength, the force comes from the dynamic pressure of the wave impact. For the vertical strength, the force comes from the viscous effect. This force is very small compared to the horizontal force (logic).

The obstacle is a vertical rectangle of 2m*1m placed at x = 8m. So the dynamic pressure is not very high but the waves are not very important.

The study had been performed to compare the results of different singelton amplitudes. But in fact, only a very small range of amplitudes can be studied because of the calculus duration that limits the box and its mesh (around 1hour for each case) and because of the fact that too high singeltons are unstable (they are broken rigth from the beginning). The fact that there is not one and only one regular peak in the graphs of the horizontal strength is not understood at that time. But this is not due to the mesh: same results had been obtained for a mesh 256*64 cells. The others results and anomalies can be understood.

The following graphs represents the value of the first maximum of the horizontal forces function of the amplitude of the singleton.

The amplitude of the singleton and the first maximum of the force seem to be lineary linked which was not expected.