Numerical and experimental investigation of three-dimensional cavitating flow around the straight NACA2412 hydrofoil

This work deals with the experimental and numerical investigation of unsteady cavitating flow around the straight NACA2412 hydrofoil with the span/chord ratio of 1.25 in the cavitation tunnel. The numerical simulations play the main part in this study; nevertheless the experimental work is also presented as an important background for validation of the results. A comprehensive CFD analysis has been carried out with three advanced turbulence models including the SAS-SST, LES-WALE and DES models. The main attention is focused on the prediction of interactions between the re-entrant flow and cavitation structures as well as the cavitation excited pressure. The monitored pressure fluctuations during the cavity cycles as well as the intervals between the dominant pressure pulses are discussed in detail. To capture side-wall effects, the whole hydrofoil and tunnel test section have been modelled, without any symmetry or periodic boundary conditions. The numerical simulations show, that the dominant frequencies of the cavity oscillation are best predicted by the SAS-SST turbulence model and the Detached Eddy Simulation. The Large Eddy Simulation has provided the best description of vortical structures in the rear part of the hydrofoil but it underestimates the side-wall effects and overestimates the dominant frequencies of the cavity oscillation. (C) 2016 Elsevier Ltd. All rights reserved.