RESUMO

The paper presents U-RANS simulations for 3-dimensional flow past a rotating cylinder for a range of Reynolds numbers and rotation rates relevant to the performance of ships propelled by Flettner rotors in place of sails. Comparisons are first drawn with existing LES data of similar flows at much lower Reynolds numbers. Thereafter the performance is examined for values of Re within the probable range of actual rotor operating conditions, including an exploration of the effect of adding discs mounted along the length of the cylinder which Thom (1934) had suggested led to improved performance at high spin rates.