Particle mixing and reactive front motion in unsteady open shallow flow - Modelled using singular value decomposition

Passive and active tracers are used to examine particle mixing and reactive front dynamics in an open shallow flow of water past a circular cylinder. A quadtree grid based Godunov-type shallow water equation solver predicts the unsteady flow hydrodynamics of the wake behind the cylinder. The resulti...

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Main Authors: Liang, Q, Taylor, P, Borthwick, A
Format: Journal article
Language:English
Published: 2007
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author Liang, Q
Taylor, P
Borthwick, A
author_facet Liang, Q
Taylor, P
Borthwick, A
author_sort Liang, Q
collection OXFORD
description Passive and active tracers are used to examine particle mixing and reactive front dynamics in an open shallow flow of water past a circular cylinder. A quadtree grid based Godunov-type shallow water equation solver predicts the unsteady flow hydrodynamics of the wake behind the cylinder. The resulting periodic flow field consisting of a von Kármán vortex street is decomposed and stored over one oscillatory period using Singular Value Decomposition (SVD). Particles are advected according to the reconstructed flow field from the SVD modes, with continuous spatial velocity information obtained via bilinear interpolation. Passive particle dynamics driven by different SVD flow modes is investigated, and it is found that the flow field recovered from the mean flow and the first pair of time varying modes is adequate to represent the complicated dynamical properties induced by the original flow field. Active autocatalytic reaction, A + B → 2B, is incorporated into the particle advection model, assuming surface reaction. Active particles are found to trace out an expanded version of the unstable manifold of the chaotic saddle in the wake, in qualitative agreement with published analytical results. The numerical model is applicable to mixing and transport processes in more complicated shallow environmental flows. © 2006 Elsevier Ltd. All rights reserved.
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spelling oxford-uuid:2a91178a-21dc-4731-9c86-c976c2ff97962022-03-26T12:25:45ZParticle mixing and reactive front motion in unsteady open shallow flow - Modelled using singular value decompositionJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:2a91178a-21dc-4731-9c86-c976c2ff9796EnglishSymplectic Elements at Oxford2007Liang, QTaylor, PBorthwick, APassive and active tracers are used to examine particle mixing and reactive front dynamics in an open shallow flow of water past a circular cylinder. A quadtree grid based Godunov-type shallow water equation solver predicts the unsteady flow hydrodynamics of the wake behind the cylinder. The resulting periodic flow field consisting of a von Kármán vortex street is decomposed and stored over one oscillatory period using Singular Value Decomposition (SVD). Particles are advected according to the reconstructed flow field from the SVD modes, with continuous spatial velocity information obtained via bilinear interpolation. Passive particle dynamics driven by different SVD flow modes is investigated, and it is found that the flow field recovered from the mean flow and the first pair of time varying modes is adequate to represent the complicated dynamical properties induced by the original flow field. Active autocatalytic reaction, A + B → 2B, is incorporated into the particle advection model, assuming surface reaction. Active particles are found to trace out an expanded version of the unstable manifold of the chaotic saddle in the wake, in qualitative agreement with published analytical results. The numerical model is applicable to mixing and transport processes in more complicated shallow environmental flows. © 2006 Elsevier Ltd. All rights reserved.
spellingShingle Liang, Q
Taylor, P
Borthwick, A
Particle mixing and reactive front motion in unsteady open shallow flow - Modelled using singular value decomposition
title Particle mixing and reactive front motion in unsteady open shallow flow - Modelled using singular value decomposition
title_full Particle mixing and reactive front motion in unsteady open shallow flow - Modelled using singular value decomposition
title_fullStr Particle mixing and reactive front motion in unsteady open shallow flow - Modelled using singular value decomposition
title_full_unstemmed Particle mixing and reactive front motion in unsteady open shallow flow - Modelled using singular value decomposition
title_short Particle mixing and reactive front motion in unsteady open shallow flow - Modelled using singular value decomposition
title_sort particle mixing and reactive front motion in unsteady open shallow flow modelled using singular value decomposition
work_keys_str_mv AT liangq particlemixingandreactivefrontmotioninunsteadyopenshallowflowmodelledusingsingularvaluedecomposition
AT taylorp particlemixingandreactivefrontmotioninunsteadyopenshallowflowmodelledusingsingularvaluedecomposition
AT borthwicka particlemixingandreactivefrontmotioninunsteadyopenshallowflowmodelledusingsingularvaluedecomposition