means of the inviscid model with respect to the experiments and to the Navier-Stokes calculation is not clear at the present stage. In more details, the gap between the two predictions seems not to be due to the separation bubble at the leading edge, otherwise the same problem would be observed when computing double model flows. Moreover, it is unlikely to be caused by geometrical linearization of the free surface, because the same condition has very little effects on the forces when applied to the Navier-Stokes calculation.
Therefore, a possible reason of such a behaviour must be sought in the nonlinear terms in the free surface boundary conditions, neglected in our inviscid computations. Another possible cause could be related to the Kutta condition imposed at the trailing edge. In fact, this condition implies continuity of the total pressure, and therefore it does not allow a free surface jump across the vortex layer. Future investigations will try to clarify the question.
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