Viscous/Inviscid hybrid approach to simulate full appended ship in self-propulsioncondition

To design an efficient propeller for ship propulsion system, open water test is a common way to investigatethe hydrodynamic behavior of propeller. The main concern in this approach is to apply the wake effect ofship stern on the propeller performance; so self-propulsion tests are performed to achieve higher accuracy.In this paper a coupled Viscous/Inviscid solver is used in order to simulate the self-propulsion test of amarine vessel. The main motivation of this effort is to develop an efficient and practical tool to designmarine propulsion system without suffering long computational time. The unsteady Boundary ElementMethod (BEM) is used as inviscid solver because of its high efficiency in calculating propellerperformance. In order to capture the trailing vortex sheet pattern of propeller during time, the unsteadyTime Stepping Method is combined with inviscid solver. On the other hand, to ascertain the effect of wakefield of the ship with acceptable accuracy, a viscous solver is chosen based on Finite Volume Method(FVM). In this solver, the Volume of Fluid approach and body attached grids is applied in order tosimulate free surface elevation and ship motion, respectively. Validation of each solver is performedseparately, and the results are compared with experimental data. Finally, by applying a coupling strategybetween two solvers, the simulation of an oceanography twin propeller Research Vessel (RV) in selfpropulsioncondition is performed. It is shown that the proposed model could estimate the thrustcoefficient of the propeller with good accuracy related to experimental self-propulsion test. The wake sheetpattern of the propeller in open water (uniform flow) is also compared with the propeller in real wake field