MARINE 2015 - Computational Methods in Marine Engineering VI

Flettner Rotors (FR) are spinning cylinders, which produce fluid dynamic lift by using the Magnus Effect. The Magnus force can be much greater in magnitude than the wing lifting force, given the same projected area and dynamic air pressure. The FR was used for ship’s propulsion system in the 1920’s. Nowadays, the FR is being seriously examined due to the necessity of renewable resources use. Since several months, the Dipartimento di Ingegneria Industriale of the Università degli Studi di Napoli “Federico II” has started a research about preliminary analysis for marine application of FR through Unsteady Reynolds Average Navier Stokes (U-RANS) simulations for 3D flow past a full-scale rotating [1]. The aerodynamic forces, Lift (L), Drag (D) and Aerodynamic Efficiency (L/D) of a FR are the response variables and are influenced by the following control factors: - Spin Ratio (SR), i.e. the ratio of circumferential-cylinder-velocity-to-free stream-velocity; - Aspect Ratio (AR), i.e. the ratio between the cylinder length and diameter; - Endplate Ratio (De/D0), i.e. ratio between the endplates diameter and cylinder diameter; In this work, a preliminary assessment of numerical setup has been conducted by comparison with experimental investigation carried out by Badalamenti and Prince at City University of London and published in [2], [3]. The tested cylinder has AR = 5.1, D0 = 0.0889 m, De/D0 = 2. A statistical approach based on Design of Experiment (DoE) has been applied to the testing program of FR in order to evaluate the functional relationship and the interaction between the control factors SR, AR and De/D0 which influence the response variables L, D and L/D. All tests are developed through U-RANS simulations for 3D flow past rotating cylinder. The U-RANS simulations have been performed by using the commercially available flow simulation software CD-Adapco STAR CCM+ v. 9.06.009