José A. Armesto

Experimentally Calibrated Time-Domain Numerical Model for a Fixed OWC Device

Oscillating Water Column technology (OWC) is one of the most promising Wave energy Converter (WEC) technologies. Different OWC devices are nowadays under development: fixed or floating, with one or several chambers. The correct understanding and efficient modelling of the simple problem of a fixed detached OWC is the basis of all of them. For this aim, a combined numerical-experimental working methodology has been followed, since it is believed to be the only way to make a real step forward in this field. Due to the high economic and time costs of experimental and field testing, the use of reliable numerical models is essential, especially during the early stages of the development. For this purpose, numerical models need to be calibrated and validated based on experimental data, ensuring realistic tools for OWC analysis. Computational Fluid Dynamics (CFD) models are widely considered the best way to analyze the dynamics involved in the problem. However, these models are complex and high computational demanding and the accuracy they offer is not necessary for a first approximation to the problem. Therefore, a simplified and faster time-domain model was built for the first stages of WEC analysis.Copyright

Methodology for Performance Assessment of a Two-Body Heave Wave Energy Converter

A wave energy farm composed by several two-body heaving wave energy converters is being developed by IH Cantabria. This study presents a methodology to obtain the power performance of an isolated two-body heaving wave energy converter, previously presented and analyzed by [1]. The methodology relies on a numerical model which represents the motion of the two bodies in the time domain. This time domain model has been built substituting the entire Cummins equation system with a state-space system, thereby avoiding the convolution integral of the radiation force term with a state-space subsystem, previously used in [2] and [3].The performance of the device along its life cycle has been estimated based on a proposed new methodology. The new method is proposed in order to obtain the long term power production of a device with the same computational effort than the classical method based on the power matrix. The proposed method is able to estimate long term power production time series. This long time series is obtained using the MaxDiss selection technique from [4] in order to compute only the power of the most representative sea states and the Radial Basis Function interpolation technique (RBF) to obtain the complete power series.Copyright