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The internal flow field characteristics of a ducted propeller set in a propeller open water test have been investigated numerically. Detached Eddy Simulation (DES) approach is employed to track the main features of the vortical structures of the internal wake field. The Spalart & Allmaras turbulence model and unsteady sliding mesh technique have been used in the simulations. Appropriate grid divided topology meeting the y+ requirement and boundary conditions set to satisfy all research objectives are discussed. The results show that the numerical hydrodynamic performance results are in good agreement with the model test. The peak value of the surface pressure fluctuation occurs in the blade passing frequency (BPF) and its multiples in the frequency domain. DES model can effectively simulate the different vortex structures of the ducted propeller, such as shear layer vortices of the duct, blade tip vortices, blade shedding vortices and blade root vortex. Tip vortex structures perform strong deformation due to the interaction between the duct and the propeller. The morphology of tip vortex changes and the vorticity distribution covers a larger area of the inner surface of the duct. All above contributes to the recovery of the propeller wake vortex energy and increases the efficiency of the propulsion.

 

Ducted propeller, DES, Pressure fluctuation, Vortex structure