  In this work a fully passive energy harvesting foil is studied
computationally. An in-house 2nd order finite volume CFD solver, MaPFlow, is
strongly coupled with a rigid body dynamics solver to investigate the foil
operation under uniform and sheared inflow conditions with/without free
surface. The mesh follows the airfoil motion using a radial basis function
(RBF) mesh deformation approach. Initially, MaPFlow predictions are compared to
experimental and numerical results available in the literature, where
reasonable agreement is found. Next, one-phase simulations are considered for
linearly sheared inflow for various shear rates. Results suggested that foil
performance can be enhanced under sheared inflow conditions. Finally, two-phase
simulations taking into account the free surface, for both uniform and sheared
inflow, are considered. Predictions indicate a significant deterioration in
performance of the system when the foil operates under the free surface due to
the interaction of the shed vorticity with the free surface.
