Influence of Laminar-to-Turbulent Transition on the Model Scale Propeller Performance and Induced Pressure Pulses in an Unsteady Case of Oblique Flow

Description

In this paper, after the successful applications to open water propeller performance estimations, the influence of transition sensitive and modified mass transfer models tuned to account for the laminar flow in the prediction of the cavitation inception of marine propulsors is investigated from the point of view of the unsteady functioning and induced pressure pulses. The VP1304 (also known as PPTC) test case, for which dedicated data were collected during several workshops, is considered first. After preliminary analyses using RANS, also Detached Eddy Simulations (DES) are included to better account for the vortex dynamics and its influence on pressure pulses. Similarly to what observed in uniform inflow, results show a better agreement with the available measurements of propeller performances and confirm the reliability of the proposed approaches for unsteady, non-cavitating, model scale propeller predictions. The overall cavitation pattern is improved too by the application of the transition sensitive correction to the mass transfer model, but the complex dynamics of bubble cavitation observed in experiments prevents quantitatively better predictions in terms of thrust/torque breakdown and induced pressure pulses levels regardless the use of RANS or DES methods.

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