Task N1.IN2: SIMULATION OF THE FLOW AROUND THE PROPELLER IN OPEN WATER TEST CONDITIONS

In the present report a numerical study of a propeller in open water conditions is carried out. The ideal model of Hough and Ordway is compared with a RANS/BEM coupled model; in both models the distribution of thrust and torque is prescribed over an actuator disk. The main differences between the two models reside in the fact that in the first the radial distribution of the body forces is prescribed regardless the real shape of the propeller blades, whereas in the second model the shape of the blades, as well as the presence of a propeller hub are taken into account. Moreover, in the RANS/BEM model the effective wake can be considered (interactive model), while in the Hough and Ordway model not (non interactive model). The main advantage for the non interactive model is the easy implementation and the negligible CPU time required. The numerical simulations have been performed at different advance ratios and inflow; in the last section simulations with an inflow with an angle of incidence are shown as a test case where the lost of symmetry occurs. The computations are conducted on a sequence of grids in order to perform an accurate analysis of the grid convergence property of the solver. The results appear to be in fairly good agreement with the computational data given in the report [2], at least at advance ratios around maximum efficiency.