Scale adaptive simulation of unsteady cavitation flow around a plane convex hydrofoil with a semi-cylindrical obstacle

The present study focuses on the numerical simulation of unsteady cavitating flow around a plane-convex hydrofoil with a semi-cylindrical obstacle, which is based on the cavitationerosion experiment perform at LMH-EPFL using the vortex cavitation generator tunnel. The turbulence model k-¿ SST SAS method, which presents advantages in terms of computational consumption and reproduction of the phenomenon, has been applied in OpenFOAM version 4 to reproduce the unsteady behavior of cavitating flow. Additionally, the Zwart-Gerber-Belamri (ZGB) cavitation model has been applied, based on a previous work where this model was implemented in OpenFOAM. The model is based on Rayleigh Plesset equation, which considers small cavities with changes of void fraction for condensation and vaporization and using empirical calibration numbers based on previous research. Regarding the mesh development, the present work explores two configurations of grid mesh containing hexahedra (hex) and split-hexahedra (split-hex) automatically generated from triangulated surface geometries based on previous numerical studies. The aforementioned method aims to optimize computational demand and phenomenon reproducibility. Results show that the unsteady cavitating flows behavior has been reproduced with good accuracy and shows special details which are important for erosion studies in futures works.Peer ReviewedPostprint (published version

Rotatory 3D structured mesh study using openFOAM to simulate the flow in francis turbine

The development of a methodology to simulate numerically the steady state flow field in Francis turbines was carried out using the open source CFD software OpenFOAM along with a MRF and AMI approach. A structured mesh obtained from previous studies was used with some modifications to solve the presence of imbalance points in the simulation. Numerical simulations using the SIMPLE algorithm were performed together with two different turbulence models. It was confirmed that the results obtained reproduced the phenomenon with a great approximation and predicted the output load with only a deviation of around 5.02% against experimental dataPeer ReviewedPostprint (published version