This paper introduces a new CFD based Immersed Body Force (IBF) model, and examines the performance of a new type of tidal turbine, the Momentum Reversal Lift (MRL) turbine, developed by Aquascientific Ltd using the open source computational fluid dynamics (CFD) code OpenFOAM. The IBF model was added as a forcing function into the existing large eddy simulation model to create a momentum change in the fluid flow induced by the MRL turbine. An experimental study was performed on a small scale model to determine the operating efficiency of the turbine and the data was used to validate the IBF model. The power output curves from both the IBF model and the experiments showed good agreement in most of the data except for a few discrepancies at higher torques, due to venturi flow created by the proximity of the computational domain's wall boundary to the turbine. Thus the results presented in this paper show the fidelity of the IBF model and can be used for different tidal turbine numerical modelling. (C) 2012 Elsevier Ltd. All rights reserved.