Peer-Reviewed Journal Details
Mandatory Fields
Wanan Sheng, Ray Alcorn, Tony Lewis
Ocean Engineering
A new method for radiation forces for floating platforms in waves
Optional Fields
Wave–structure interaction Hybrid frequency–time domainanalyses Waveenergyconversion Impulse responsefunction Memory effect The Cummins–Ogilvie equation
The performance of wave energy converters and other offshore renewable energy platforms, non-linear effects is frequently assessed in time domain, especially when the nonlinear forces from the large amplitude motions, mooring forces, power take-off or the energy conversion control system are considered. One popular approach in the time-domain analysis is the so-called hybrid frequency-time domain analysis, in which the radiation forces must be calculated through a convolution integral of the motion history and the impulse response function. The direct integration of the convolution is not only time-consuming and inconvenient when a real time control is used, but also needs a storage and renewal of a certain history of motions. To this end, some approximation methods have been developed for calculating the memory effect, and these methods inevitably introduce additional equations into the dynamic system. In this paper, a new method is proposed for calculating the memory effect by extending the conventional Prony’s function method so that the memory effect calculation can be carried out simply in a recursive manner. As a result of the recursive calculation, only one previous step of the values is needed, which can be renewed automatically in each time step calculation.
Grant Details