Improved modelling of sheet cavitation dynamics on delft twist11 hydrofoil

Abstract

In this paper, unsteady viscous-flow cavitation predictions for a 3D hydrofoil are performed using three different approaches: 1) a pure RANS method; 2) a RANS method including an eddy-viscosity “Reboud” correction; 3) a DDES Scale-Resolving-Simulation approach. Both wetted and cavitating flow conditions are analysed and compared with experimental data. The accuracy of these approaches is scrutinised in terms of integral quantities, cavity dynamics, different background principles, and the influence of grid refinement. Low numerical uncer- tainties have been obtained for wetted flow conditions, but a somewhat large deviation on the wing loading has been observed when compared with experimental results. For the cavitating flow case, the RANS calculations do not accurately simulate the cavity dynamics. The RANS- Reboud correction improves the fidelity of the calculations at increased numerical demands and decreased robustness. The DDES approach leads to improved dynamics, slightly less accurate cavity shedding mechanism, at lower computational cost. The cavity extents are underpredicted for all methods and conditions used, when compared with the available experimental data.