Non-negative intensity for coupled fluid-structure interaction problems using the fast multipole method

Daniel R. Wilkes, Herwig Peters, Paul Croaker, Steffen Marburg, Alec J. Duncan, Nicole Kessissoglou

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

The non-negative intensity (NNI) method is applied to large-scale coupled fluid-structure interaction (FSI) problems using the fast multipole boundary element method (FMBEM). The NNI provides a field on the radiating structure surface that consists of positive-only contributions to the radiated sound power, thus avoiding the near-field cancellation effects that otherwise occur with the sound intensity field. Thus far the NNI has been implemented with the boundary element method (BEM) for relatively small problem sizes to allow for the full BEM coefficient and inverse matrices to be explicitly constructed and stored. In this work, the FMBEM is adapted to the NNI by calculating the eigenvalue solution of the symmetric acoustic impedance matrix using the FMBEM via a two-stage solution method. The FMBEM implementation of the NNI is demonstrated for a largescale model of a submerged cylindrical shell. The coupled FSI problem is first solved using a finite element-FMBEM model and the resulting surface fields are then used in the FMBEM calculation of the NNI. An equivalent reactive NNI field representing the evanescent near-field radiation is demonstrated and the effect of the chosen number eigenvectors on the NNI field is investigated.

Original languageEnglish
Pages (from-to)4278-4288
Number of pages11
JournalJournal of the Acoustical Society of America
Volume141
Issue number6
DOIs
StatePublished - Jun 2017

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