Prediction of unsteady propeller performance in an inhomogeneous wake

Accurate prediction of unsteady propeller loads for propellers operating in non-uniform flow (i.e. the wake of a ship hull) is vital for assessing the suitability of candidate propellers in the context of noise and onboard vibration. This requires an assessment of the flow around the hull, the response of the propeller to the incident flow, and the propeller interactions with the flow field and other appendages/surfaces. This paper examines a subset of these by evaluating the suitability of several computational codes for assessing the unsteady response of a model propeller to wake inhomogeneity. The motivation for this work is to better understand the trade-off between ac-curacy and computational cost. This understanding allows for a more robust investigation of the design parameter space. Unsteady thrust and torque predictions from the Boundary Element Method (BEM) code PROCAL and Unsteady-RANS solver Star-CCM+ are compared with a prediction from the unsteady lifting surface theory code PUF-2 and experimental measurements carried out at the David Taylor Research Centre (DTRC). To reproduce the experimental conditions with Unsteady Reynolds Averaged-Navier Stokes (URANS), a consistent method-ology for representing the wake field is introduced. It is found that the BEM method can provide predictions with accuracy close to that of the URANS calculations for low frequency harmonics.