Three-dimensional CFD simulations of a rigid, square panel pitching about its leading edge were performed by solving the governing equations in a non-inertial reference frame moving with the body using a solver developed under the OpenFOAM environment. The accuracy of the code is established by comparisons with experiment and DNS. The solver is then used to study the three-dimensional flow field around a rigid propulsor with a square planform pitching about its leading edge. The simulations span the range 500 < Re < 16000 and 0.1 < St < 1.0. Thrust and efficiency characteristics are determined with a peak efficiency of eta approximate to 10% at St = 0.4 and Re = 16000. The thrust is dependent of Reynolds number for Re <= 8000, and although the efficiency is more sensitive to Reynolds number, for Re > 8000 there is only a weak dependence. By examining the pressure and shear stress distributions on the panel, the dominant contribution to the thrust is found to be the segment of the panel corresponding to the interval 0.625c - 0.75c. The leading and trailing edges are found to generate drag in most cases. Wake visualizations help to identify the wake state and to understand the vortex formation on the panel edges. (C) 2017 Elsevier Ltd. All rights reserved.