Summary: A generic two-fluid (water/air) numerical model has been developed and applied for the simulation of the complex fluid flow around a wave-driven rotating vane near a shoreline in the context of a novel wave energy device OWSC (Oscillating wave surge converter). The underlying scheme is based on the solution of incompressible Euler equations for a variable density fluid system for automatically capturing the interface between water and air, and on the Cartesian cut cell method for tracking moving solid boundaries on a background stationary Cartesian grid. The results from the present study indicate that the method is an effective tool for modeling a wide range of free surface flow problems.