Waterjet Self-Propulsion Simulation: A Body-Force Approach for Modelling the Pump

Paper in proceeding, 2017

The waterjet pump can be treated in different ways in a Reynolds Averaged Navier-Stokes based numerical simulation. The most accurate model is to resolve the complete pump geometry with rotating impeller (e.g. rigid body rotation). Alternatively, in order to reduce the computational cost, a frozen rotor approach or a body-force model can be employed. In this paper, different body-force models are utilized to simulate the waterjet pump in self-propulsion. Then the body-force models are evaluated through a quantitative comparison of the pump flow rate, head rise and the detailed flow at the nozzle exit with the results obtained from the more sophisticated rigid body rotation and frozen rotor techniques. This evaluation reveals that a body-force model for pump induces very similar effects on the flow in comparison to the more sophisticated methods and can reliably be used for modelling waterjet-hull interaction effects in self-propulsion.