An Open Boundary Condition for Numerical Coastal Circulation Models

Open boundaries (OBs) are usually unavoidable in numerical coastal circulation simulations. At OBs, an appropriate open boundary condition (OBC) is required so that outgoing waves freely pass to the exterior without creating reflections back into the interior of the computational domain. In this pap...

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Main Authors: Madsen, Ole S., Ma, Peifeng
Other Authors: Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
Format: Article
Language:en_US
Published: American Meteorological Society 2012
Online Access:http://hdl.handle.net/1721.1/71735
https://orcid.org/0000-0002-6984-6499
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author Madsen, Ole S.
Ma, Peifeng
author2 Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
author_facet Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
Madsen, Ole S.
Ma, Peifeng
author_sort Madsen, Ole S.
collection MIT
description Open boundaries (OBs) are usually unavoidable in numerical coastal circulation simulations. At OBs, an appropriate open boundary condition (OBC) is required so that outgoing waves freely pass to the exterior without creating reflections back into the interior of the computational domain. In this paper, the authors derive, based on the shallow-water equations including bottom friction and neglecting Coriolis effect and by means of nonlinear characteristic analysis, an OBC formulation with two predictive parameters, phase speed c[subscript r], and decay time T[subscript f]. Simple idealized tests are performed to demonstrate the proposed OBC’s excellent skills in elimination of unwanted reflections at OBs when the motion is periodic, as assumed in its theoretical derivation. It turns out that the formulas for the two OBC parameters become independent of period in the limit of small friction and/or short period. This feature is used to derive an OBC applicable when information about the typical period of the motion to be simulated is unavailable. Simple, idealized tests of this period independent OBC demonstrate its ability to afford excellent results, even when the limitations inherent in its derivation are exceeded. Finally, the OBC is applied in more realistic simulations, including Coriolis effects of 2D tidal flows, and is shown to yield excellent results, especially for residual flows.
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spelling mit-1721.1/717352022-09-27T20:51:42Z An Open Boundary Condition for Numerical Coastal Circulation Models Madsen, Ole S. Ma, Peifeng Massachusetts Institute of Technology. Department of Civil and Environmental Engineering Madsen, Ole S. Madsen, Ole S. Open boundaries (OBs) are usually unavoidable in numerical coastal circulation simulations. At OBs, an appropriate open boundary condition (OBC) is required so that outgoing waves freely pass to the exterior without creating reflections back into the interior of the computational domain. In this paper, the authors derive, based on the shallow-water equations including bottom friction and neglecting Coriolis effect and by means of nonlinear characteristic analysis, an OBC formulation with two predictive parameters, phase speed c[subscript r], and decay time T[subscript f]. Simple idealized tests are performed to demonstrate the proposed OBC’s excellent skills in elimination of unwanted reflections at OBs when the motion is periodic, as assumed in its theoretical derivation. It turns out that the formulas for the two OBC parameters become independent of period in the limit of small friction and/or short period. This feature is used to derive an OBC applicable when information about the typical period of the motion to be simulated is unavailable. Simple, idealized tests of this period independent OBC demonstrate its ability to afford excellent results, even when the limitations inherent in its derivation are exceeded. Finally, the OBC is applied in more realistic simulations, including Coriolis effects of 2D tidal flows, and is shown to yield excellent results, especially for residual flows. 2012-07-20T18:18:25Z 2012-07-20T18:18:25Z 2011-12 2010-09 Article http://purl.org/eprint/type/JournalArticle 0022-3670 1520-0485 http://hdl.handle.net/1721.1/71735 Ma, Peifeng, and Ole Secher Madsen. “An Open Boundary Condition for Numerical Coastal Circulation Models.” Journal of Physical Oceanography 41.12 (2011): 2363–2380. © 2011 American Meteorological Society https://orcid.org/0000-0002-6984-6499 en_US http://dx.doi.org/10.1175/2011jpo4574.1 Journal of Physical Oceanography Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Meteorological Society American Meteorological Society
spellingShingle Madsen, Ole S.
Ma, Peifeng
An Open Boundary Condition for Numerical Coastal Circulation Models
title An Open Boundary Condition for Numerical Coastal Circulation Models
title_full An Open Boundary Condition for Numerical Coastal Circulation Models
title_fullStr An Open Boundary Condition for Numerical Coastal Circulation Models
title_full_unstemmed An Open Boundary Condition for Numerical Coastal Circulation Models
title_short An Open Boundary Condition for Numerical Coastal Circulation Models
title_sort open boundary condition for numerical coastal circulation models
url http://hdl.handle.net/1721.1/71735
https://orcid.org/0000-0002-6984-6499
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