Lopes, D. B. S.D. B. S.LopesVaz, G.G.VazFalcão de Campos, J. A. C.J. A. C.Falcão de CamposSarmento, A. J. N. A.A. J. N. A.Sarmento2024-04-172024-04-172024-04-048th International Symposium on Marine Propulsors (smp 2024)978-82-691120-5-4https://hdl.handle.net/11420/46483The present work investigates free-surface effects on the dynamics of tandem oscillating foils in two-dimensional flow. The study comprises the cases in infinite domain, with and without an incident wave. A CFD solver with a URANS approach is used to model the flow around the tandem foil and the effects of the free-surface. A robust deforming grid method is used for body motion modelling, enabling large motions of the foils. Results of wake patterns and forces acting on the foils are presented for a high performance configuration. A complementary study uses a semi-analytical model based on Theodorsen unsteady theory. This formulation is extended to allow for the application to large motions and the interaction of both foils, including free-surface effects, and incident waves. The case of the tandem foil in waves shows very promising results. The high performance configuration reached high values of thrust and propulsive efficiency with increases in thrust of 38% when compared with the sum of two isolated single foils.enhttp://rightsstatements.org/vocab/InC/1.0/Oscillating hydrofoilsWave propulsionTandem foilHydrofoil modellingCFDEngineering and Applied OperationsConference Paper10.15480/882.934610.15480/882.934610.15480/882.9294Conference Paper