Submarine propeller computations and application to self-propulsion of DARPA Suboff

Simulations of the submarine propeller E1619 using the overset flow solver CFDShip-Iowa V4.5 are presented. Propeller open water curves were obtained for two grids for a wide range of advance coefficients covering high to moderately low loads, and results compared with available experimental data. A verification study was performed for one advance coefficient (J=0.71) on four grids and three time step sizes. The study shows that grid refinement has a weak effect on thrust and torque but very strongly affects the wake. The effect of the turbulence model on the wake was evaluated at J=0.4 comparing results with RANS, DES, DDES and with no turbulence model, showing that RANS overly dissipates the wake and that in the solution with no turbulence model the tip vortices quickly become unphysically unstable. Tip vortex pairing is observed and described for J≤0.71, showing multiple vortices merging for higher loads. The wake velocities are compared against experimental data for J=0.74, showing good agreement. Self-propulsion computations of the DARPA Suboff generic submarine hull fitted with sail, rudders, stern planes and the E1619 propeller were performed in model scale and the resulting propeller performance analyzed.