The Oscillating Water Column is one of the oldest concepts for wave energy harvesting. T e device optimization is still a crucial point for the commercial-scale diffusion of this technology. Therefore, research at fundamental level is still required. The implementation and the application a CFD code for the conduction of a parameter study aiming at the optimization of the device is presented. The numerical set up and the validation of a virtual wave flume in the open-source environment OpenFOAM® are initially presented, using comparatively different wave generation approaches. The application of the model to simulate the device and a validation with physical results are shown. The model solves incompressible 3D Navier-Stokes equations for a single Eulerian fluid mixture of water and air, using a Finite Volume Method for equations discretization and the Volume Of Fluid method for free surface tracking. Different turbulence models are tested, comparing their suitability for this particular application both in terms of computational cost and model capability to reproduce the experimental data.