POWER ABSORPTION BY ARRAYS OF INTERACTING VERTICAL AXISYMMETRIC WAVE-ENERGY DEVICES
S.A. Mavrakos(*) and A. Kalofonos (**), National Technical University of Athens, Department of Naval Architecture and Marine Engineering, 9 Heroon Polytechniou Ave., 157 73 Zografos/Athens, Greece, (*) Assoc. Prof. of Offshore Structures, (**) Naval Architect
ABSTRACT
The paper deals with the evaluation of the optimum wave-power absorption characteristics of arrays of interacting wave-energy devices. The hydrodynamic interference effects among the devices are exactly accounted for using a method that can solve the problem to any desired accuracy. The method is based on single body hydrodynarnic characteristics that are properly combined through the physical idea of multiple scattering to account for interaction effects. Extensive numerical results for a variety of different array arrangements and individual device geometries are presented and comparisons are made to predictions based on approximate theories, the accuracy of which is critically assessed
OPTIMAL CONTROL OF WAVE ENERGY DEVICES WITH VARIOUS POWER-TAKE-OFF MECHANISMS
Nancy K. Nichols and Amanda Crossley, Department of Mathematics, University of Reading, Box22O Whiteknights, Reading RG6 6AF
ABSTRACT
The aims of this research are to develop and test methods for analysing and computing optimal control strategies for maximizing the useful power generated from wave energy con verters incorporating realistic power-take-off and control mechanisms. Previously, strategies for maximizing energy absorbed by wave devices have been investigated, but these studies have assumed an ideal conversion rate using perfectly efficient turbomachinery with no constraints imposed by the generator capacity.
In this paper various turbine characteristics and control mechanisms incorporating nonlinear losses are modelled, the qualitative properties of the optimal control strategy for maximizing average power delivered at the turbine shaft are analyzed, computational techniques for determining numerical solutions to the optimal control problem are established and the results are tested on a fully developed hydrodynamic model of a wave energy device.
