Numerical models have been used recently to quantify the effects of tidal extraction in specific tidal systems. Commonly, these studies have employed numerical approximations to the depth-averaged shallow water equations to simulate tidal hydrodynamics. Tidal power extraction has then been introduced by incorporating an additional bed shear source term, or another general source term, to represent the presence of tidal devices.
We review these models and adopt an approach, based on actuator disc theory, to define the properties of a tidal device within a depth-averaged numerical model. This approach allows a direct link to be made between the actual tidal device and the equivalent momentum sink that the device should impart within a two dimensional (2D) depth-averaged domain. We use this description of a tidal device to model the hydrodynamic effects of energy extraction in an arbitrary coastal domain.