Kelly, Thomas and Zabala, Inaki and Peña-Sanchez, Yerai and Penalba, Markel and Ringwood, John and Henriques, João and Blanco, Jesús (2021) A post-processing technique for addressing ‘irregular frequencies’ and other issues in the results from BEM solvers. In: 14th European Wave and Tidal Energy Conference, 5-9th Sept 2021, Plymouth, UK.

Preview

Download (1MB) | Preview

Abstract

Within the wave energy community, hydrodynamic coefficients obtained from boundary element methods (BEMs) are commonly used to predict the behaviour of wave energy converters (WECs) in response to incident waves. A number of commercially-available BEM solvers exist, with a number of open-source alternatives also available. While open-source solvers have an obvious cost advantage compared to their commercial counterparts, the results from such solvers are often susceptible to so-called ‘irregular frequencies’, which arise from ill-conditioning in boundary integral problems, and result in large under or over-estimation of hydrodynamic parameters at certain excitation frequencies. Furthermore, while commercial solvers may employ techniques to suppress the effects of irregular frequencies, such solvers may, under certain circumstances, exhibit other problems in the hydrodynamic results produced. For example, the results obtained for the added mass at high frequencies, and the infinite frequency added mass for a water column, may be incorrect. The current work first focusses on an approach to remove the effects of irregular frequencies from the results obtained for the radiation damping of a particular WEC geometry. The use of radiation damping results to obtain values for the added mass, through the use of the Ogilvie relations, is then considered. The technique described herein has been implemented in BEMRosetta, an open-source tool which allows a user to view the results from various BEM solvers, as well as converting input files between solvers. The results presented in this paper have been obtained using the BEMRosetta implementation.

Item Type:	Conference or Workshop Item (Paper)
Keywords:	Boundary element methods; Irregular frequencies; Numerical modelling;
Academic Unit:	Faculty of Science and Engineering > Electronic Engineering Faculty of Science and Engineering > Research Institutes > Centre for Ocean Energy Research
Item ID:	16248
Depositing User:	Professor John Ringwood
Date Deposited:	15 Jul 2022 10:20
Refereed:	Yes
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

Repository Staff Only(login required)

Item control page

Downloads

Origin of downloads