Implementation of latching control in a numerical wave tank with regular waves

In order to increase the overall power production efficiency of wave energy technology in the face of sea state variability, the presence of the control is mandatory. A model of the system is required to tune the controller parameters and predict the resulting performances. Even though the relevance of nonlinearities is magnified by the presence of the controller, the device model employed is usually linear. An implementation of control in a fully nonlinear simulation model is desirable, but missing. Hence, this paper proposes to use the fully nonlinear computational fluid dynamics (CFD) environment, implementing the latching control strategy in the open source software OpenFOAM. A case study has been analyzed to highlight the nonlinear behavior of a device under latching control and to evaluate the differences between linear and nonlinear simulation models. The results show that the linear model overestimates the amplitude of motion, and, as a result, the extracted power. Moreover, the choice of the optimal control parameter is significantly affected by the nonlinear effect on the natural period of the device.