UKERC EDC: ETI

Citation	S. Draycott, S., Davey, T., Ingram, D.M., Day, A. and Johanning, L. The SPAIR method: Isolating incident and reflected directional wave spectra in multidirectional wave basins, Coastal Engineering, 114: 265-283, 2017. https://doi.org/10.1016/j.coastaleng.2016.04.012. Cite this using DataCite
Author(s)	S. Draycott, S., Davey, T., Ingram, D.M., Day, A. and Johanning, L.
Project partner(s)	FloWave Ocean Energy Research Facility, University of Edinburgh, University of Exeter, University of Strathclyde,
Publisher	Coastal Engineering, 114: 265-283
DOI	https://doi.org/10.1016/j.coastaleng.2016.04.012
Abstract	Wave tank tests aiming to reproduce realistic or site specific conditions will commonly involve using directionally spread, short-crested sea states. The measurement of these directional characteristics is required for the purposes of calibrating and validating the modelled sea state. Commonly used methods of directional spectrum reconstruction, based on directional spreading functions, have an inherent level of uncertainty associated with them. In this paper we aim to reduce the uncertainty in directional spectrum validation by introducing the SPAIR (Single-summation PTPD Approach with In-line Reflections) method, in combination with a directional wave gauge array. A variety of wave conditions were generated in the FloWave Ocean Energy Research Facility, Edinburgh, UK, to obtain a range of sea state and reflection scenarios. The presented approach is found to provide improved estimatesof directional spectra over standard methods, reducing the mean apparent directional deviation down to below 6% over the range of sea states. Additionally, the method isolates incident and reflected spectra in both the frequency and time domain, and can separate these wave systems over 360. The accuracy of the method is shown to be only slightly sensitive to the level of in-line reflection present, but at present cannot deal with oblique reflections. The SPAIR method, as presented or with slight modification, will allow complex directional sea states to be validated more effectively, enabling multidirectional wave basins to simulate realistic wave scenarios with increased confidence. Highlights An effective combined wave generation-measurement approach is presented. The method is trialled at a unique circular wave tank, FloWave. It is shown to reduce the directional spectrum measurement error significantly. Isolates incident and reflected directional spectra in frequency and time domain Reduces uncertainty in the use of complex, directional sea states This work was partly funded via IDCORE, the Industrial Doctorate Centre for Offshore Renewable Energy, which trains research engineers whose work in conjunction with sponsoring companies aims to accelerate the deployment of offshore wind, wave and tidal-current technologies
Associated Project(s)	ETI-MA2003: Industrial Doctorate Centre for Offshore Renewable Energy (IDCORE)
Associated Dataset(s)	No associated datasets
Associated Publication(s)	A model to map levelised cost of energy for wave energy projects An Integrated Data Management Approach for Offshore Wind Turbine Failure Root Cause Analysis An investigation of the effects of wind-induced inclination on floating wind turbine dynamics: heave plate excursion Application of an offshore wind farm layout optimization methodology at Middelgrunden wind farm Characterisation of current and turbulence in the FloWave Ocean Energy Research Facility Characterization of the tidal resource in Rathlin Sound Comparison of Offshore Wind Farm Layout Optimization Using a Genetic Algorithm and a Particle Swarm Optimizer Component reliability test approaches for marine renewable energy Constraints Implementation in the Application of Reinforcement Learning to the Reactive Control of a Point Absorber Control of a Realistic Wave Energy Converter Model Using Least-Squares Policy Iteration Cost Reduction to Encourage Commercialisation of Marine in the UK Cumulative impact assessment of tidal stream energy extraction in the Irish Sea Design diagrams for wavelength discrepancy in tank testing with inconsistently scaled intermediate water depth Development of a Condition Monitoring System for an Articulated Wave Energy Converter Dynamic mooring simulation with Code(-)Aster with application to a floating wind turbine ETI Insights Report - Wave Energy Environmental interactions of tidal lagoons: A comparison of industry perspectives Exploring Marine Energy Potential in the UK Using a Whole Systems Modelling Approach Hybrid, Multi-Megawatt HVDC Transformer Topology Comparison for Future Offshore Wind Farms Hydrodynamic analysis of a ducted, open centre tidal stream turbine using blade element momentum theory Offshore wind farm electrical cable layout optimization Offshore wind installation vessels - A comparative assessment for UK offshore rounds 1 and 2 Optimisation of Offshore Wind Farms Using a Genetic Algorithm Quantifying uncertainty in acoustic measurements of tidal flows using a “Virtual” Doppler Current Profiler Re-creation of site-specific multi-directional waves with non-collinear current Reactive control of a two-body point absorber using reinforcement learning Reactive control of a wave energy converter using artificial neural networks Reliability and O & M sensitivity analysis as a consequence of site specific characteristics for wave energy converters Reliability prediction for offshore renewable energy: Data driven insights Resource characterization of sites in the vicinity of an island near a landmass Review and application of Rainflow residue processing techniques for accurate fatigue damage estimation Sensitivity analysis of offshore wind farm operation and maintenance cost and availability Simulating Extreme Directional Wave Conditions Testing Marine Renewable Energy Devices in an Advanced Multi-Directional Combined Wave-Current Environment Testing the robustness of optimal access vessel fleet selection for operation and maintenance of offshore wind farms The Industrial Doctorate Centre for Offshore Renewable Energy(IDCORE) - Case Studies The effects of wind-induced inclination on the dynamics ofsemi-submersible floating wind turbines in the time domain The power-capture of a nearshore, modular, flap-type wave energy converter in regular waves UK offshore wind cost optimisation: top head mass (Presentation to All Energy, 10th May 2017)

The SPAIR method: Isolating incident and reflected directional wave spectra in multidirectional wave basins