Validation of a CFD-Based Numerical Wave Tank Model of the 1/20th Scale Wavestar Wave Energy Converter

Christian Windt,Yerai Peña-Sanchez,Nicolás Faedo,Francesco Ferri,Demián García-Violini,Josh Davidson,John V Ringwood

doi:10.3390/fluids5030112

Abstract

Numerical wave tanks (NWTs) provide efficient test beds for the numerical analysis at various stages during the development of wave energy converters (WECs). To ensure the acquisition of accurate, high-fidelity data sets, validation of NWTs is a crucial step. However, using experimental data as reference during model validation, exact knowledge of all system parameters is required, which may not always be available, thus making an incremental validation inevitable. The present paper documents the numerical model validation of a 1/20 scale Wavestar WEC. The validation is performed considering different test case of increasing complexity: wave-only, wave excitation force, free decay, forced oscillation, and wave-induced motion cases. The results show acceptable agreement between the numerical and experimental data so that, under the well-known modelling constraints for mechanical friction and uncertainties in the physical model properties, the developed numerical model can be declared as validated.

Highlights

The numerical modelling of the wave-structure interaction (WSI) is an integral part of the development of wave energy converters (WECs), complementing physical wave tank tests.Compared to physical wave tanks, numerical wave tanks (NWTs) provide an excellent numerical tool, allowing the investigation of different WEC designs and scales, with the ability to passively measure relevant variables at arbitrary locations throughout the Numerical wave tanks (NWTs)
To ensure high-fidelity of the generated data, computational fluid dynamics (CFD)-based NWTs rely on both verification and validation [1]
Validation covers the comparison of numerical results to reference data

Summary

Introduction

The numerical modelling of the wave-structure interaction (WSI) is an integral part of the development of wave energy converters (WECs), complementing physical wave tank tests. Compared to physical wave tanks, numerical wave tanks (NWTs) provide an excellent numerical tool, allowing the investigation of different WEC designs and scales, with the ability to passively measure relevant variables at arbitrary locations throughout the NWT. Computational fluid dynamics (CFD)-based NWTs can provide high-fidelity data sets to support the WEC development. To ensure high-fidelity of the generated data, CFD-based NWTs rely on both verification and validation [1]. Verification embraces the quantification of spatial and temporal discretisation errors using convergence studies. Validation covers the comparison of numerical results to reference data

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Conclusion