Giorgi, Giuseppe and Ringwood, John (2017) Consistency of Viscous Drag Identification Tests for Wave Energy Applications. Proceedings of the 12th European Wave and Tidal Energy Conference 27th Aug -1st Sept 2017 (643). pp. 1-8. ISSN 2309-1983

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Abstract

Viscous drag forces in mathematical models for wave energy converters are usually modelled by means of a term based on the Morison equation. Due to large relative velocities, induced by control strategies in order to increase the power absorption,viscous losses can have a high impact on the model accuracy and,in turn, on the model-based power optimization control strategies.Notwithstanding the importance of a reliable estimation of the drag coefficient in the Morison equation, much inconsistency and low trustworthiness is found in the literature, about both the values themselves, and the identification methods.Indeed, drag identification for wave energy applications is particularly challenging, mainly due to the device dimensions,characteristic flow regimes, large motions and, in particular, the presence of the free surface. An ideal identification test would be able to replicate the full complexity of the flow, and concurrently to isolate viscous forces from other forces and nonlinear effects.This paper seeks to discuss the inherent challenges to drag identification, proper to wave energy applications. Moreover,different identification techniques are implemented, evaluated and compared, with regard to the estimation of the drag coefficient for a floating heaving point absorber.

Item Type:	Article
Keywords:	Nonlinear modelling; viscous drag coefficient; Morison equation; computational fluid dynamics; wave energy converters;
Academic Unit:	Faculty of Science and Engineering > Electronic Engineering Faculty of Science and Engineering > Research Institutes > Centre for Ocean Energy Research
Item ID:	12456
Depositing User:	Professor John Ringwood
Date Deposited:	12 Feb 2020 16:51
Journal or Publication Title:	Proceedings of the 12th European Wave and Tidal Energy Conference 27th Aug -1st Sept 2017
Publisher:	European Wave and Tidal Energy Conference 2017
Refereed:	Yes
Funders:	Science Foundation Ireland (SFI)
URI:
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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