A novel vertical axis wind turbine (VAWT) has been developed that consists of several asymmetric vertically-stacked stages. A computational investigation of the torque characteristics of the VAWT has been conducted using the commercial computational fluid dynamics (CFD) software CFdesign 2010. A validation study consisting of steady and rotating simulations was conducted using a Savonius rotor and good agreement was obtained with experimental data. Steady two-dimensional CFD simulations have demonstrated that the new VAWT has similar average static torque characteristics to existing Savonius rotors. Rotating three-dimensional CFD simulations were conducted at several tip speed ratios with a freestream speed of 6 m/s. The predicted dynamic torque generated by the rotor decays more rapidly with increasing tip speed ratio than the torque output of Savonius rotors due to its asymmetric design and the curvature of the outer rotor wall. (C) 2011 Elsevier Ltd. All rights reserved.