Non linear shallow water modelling of bore-driven swash:  Description of the bottom boundary layer

Riccardo Briganti; Nicholas Dodd; Dubravka Pokrajac; Tom O'Donoghue

doi:10.1016/j.coastaleng.2011.01.004

Non linear shallow water modelling of bore-driven swash: Description of the bottom boundary layer

Riccardo Briganti, Nicholas Dodd, Dubravka Pokrajac, Tom O'Donoghue

Engineering

Fac Engn

Research output: Contribution to journal › Article › peer-review

43 Citations (Scopus)

Abstract

The paper presents a simple approach to estimate the bottom shear stress in the swash zone by coupling the Non Linear Shallow Water Equations with the momentum integral equation for the bottom boundary layer. The approach allows not only the computation of the frictional dissipation term in the equations but also to have an insight into the flow structure in the water column during a swash event. The numerical results have been compared with a new set of experiments involving a single dam-break generated swash event. Three different grain sizes, ranging from coarse sand to gravel, have been tested in the laboratory.

A sensitivity analysis on the only calibration parameter of the model, the bed roughness, is presented and its optimal value is chosen. The numerically predicted free surface, depth averaged velocity and velocity profiles have been compared with the measured ones. Results are very good in the run-up stage, where also the bottom shear stress is well modelled. In the backwash the frictional energy dissipation is better modelled for the gravel beach than for the coarse sand one. Results show that the simple model accurately predicts the flow parameters during the swash event. Also the velocity profiles are reasonably well predicted, especially during the run-up. (C) 2011 Elsevier B.V. All rights reserved.

Original language	English
Pages (from-to)	463-477
Number of pages	15
Journal	Coastal Engineering
Volume	58
Issue number	6
Early online date	23 Feb 2011
DOIs	https://doi.org/10.1016/j.coastaleng.2011.01.004
Publication status	Published - Jun 2011

Bibliographical note

A paid open access option is available for this journal.
Voluntary deposit by author of pre-print allowed on Institutions open scholarly website and pre-print servers
Voluntary deposit by author of authors post-print allowed on institutions open scholarly website including Institutional Repository
Deposit due to Funding Body, Institutional and Governmental mandate only allowed where separate agreement between repository and publisher exists
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Published source must be acknowledged
Must link to journal home page or articles' DOI
Publisher's version/PDF cannot be used
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NIH Authors articles will be submitted to PubMed Central after <num>12</num> <period units="month">months</period>
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Keywords

Bore-driven swash
Shock capturing schemes
Bottom boundary layer
Bottom shear stress
Momentum integral method
Flow
Bed
Beach

Access to Document

10.1016/j.coastaleng.2011.01.004

Cite this

@article{4d7b26e82c9e4cc58cd528f4360c96bb,

title = "Non linear shallow water modelling of bore-driven swash: Description of the bottom boundary layer",

abstract = "The paper presents a simple approach to estimate the bottom shear stress in the swash zone by coupling the Non Linear Shallow Water Equations with the momentum integral equation for the bottom boundary layer. The approach allows not only the computation of the frictional dissipation term in the equations but also to have an insight into the flow structure in the water column during a swash event. The numerical results have been compared with a new set of experiments involving a single dam-break generated swash event. Three different grain sizes, ranging from coarse sand to gravel, have been tested in the laboratory.A sensitivity analysis on the only calibration parameter of the model, the bed roughness, is presented and its optimal value is chosen. The numerically predicted free surface, depth averaged velocity and velocity profiles have been compared with the measured ones. Results are very good in the run-up stage, where also the bottom shear stress is well modelled. In the backwash the frictional energy dissipation is better modelled for the gravel beach than for the coarse sand one. Results show that the simple model accurately predicts the flow parameters during the swash event. Also the velocity profiles are reasonably well predicted, especially during the run-up. (C) 2011 Elsevier B.V. All rights reserved.",

keywords = "Bore-driven swash, Shock capturing schemes, Bottom boundary layer, Bottom shear stress, Momentum integral method, Flow, Bed, Beach",

author = "Riccardo Briganti and Nicholas Dodd and Dubravka Pokrajac and Tom O'Donoghue",

note = "A paid open access option is available for this journal. Voluntary deposit by author of pre-print allowed on Institutions open scholarly website and pre-print servers Voluntary deposit by author of authors post-print allowed on institutions open scholarly website including Institutional Repository Deposit due to Funding Body, Institutional and Governmental mandate only allowed where separate agreement between repository and publisher exists Set statement to accompany deposit Published source must be acknowledged Must link to journal home page or articles' DOI Publisher's version/PDF cannot be used Articles in some journals can be made Open Access on payment of additional charge NIH Authors articles will be submitted to PubMed Central after <num>12</num> <period units={"}month{"}>months</period> Authors who are required to deposit in subject-based repositories may also use Sponsorship Option",

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AU - Dodd, Nicholas

AU - Pokrajac, Dubravka

AU - O'Donoghue, Tom

N1 - A paid open access option is available for this journal. Voluntary deposit by author of pre-print allowed on Institutions open scholarly website and pre-print servers Voluntary deposit by author of authors post-print allowed on institutions open scholarly website including Institutional Repository Deposit due to Funding Body, Institutional and Governmental mandate only allowed where separate agreement between repository and publisher exists Set statement to accompany deposit Published source must be acknowledged Must link to journal home page or articles' DOI Publisher's version/PDF cannot be used Articles in some journals can be made Open Access on payment of additional charge NIH Authors articles will be submitted to PubMed Central after <num>12</num> <period units="month">months</period> Authors who are required to deposit in subject-based repositories may also use Sponsorship Option

PY - 2011/6

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N2 - The paper presents a simple approach to estimate the bottom shear stress in the swash zone by coupling the Non Linear Shallow Water Equations with the momentum integral equation for the bottom boundary layer. The approach allows not only the computation of the frictional dissipation term in the equations but also to have an insight into the flow structure in the water column during a swash event. The numerical results have been compared with a new set of experiments involving a single dam-break generated swash event. Three different grain sizes, ranging from coarse sand to gravel, have been tested in the laboratory.A sensitivity analysis on the only calibration parameter of the model, the bed roughness, is presented and its optimal value is chosen. The numerically predicted free surface, depth averaged velocity and velocity profiles have been compared with the measured ones. Results are very good in the run-up stage, where also the bottom shear stress is well modelled. In the backwash the frictional energy dissipation is better modelled for the gravel beach than for the coarse sand one. Results show that the simple model accurately predicts the flow parameters during the swash event. Also the velocity profiles are reasonably well predicted, especially during the run-up. (C) 2011 Elsevier B.V. All rights reserved.

AB - The paper presents a simple approach to estimate the bottom shear stress in the swash zone by coupling the Non Linear Shallow Water Equations with the momentum integral equation for the bottom boundary layer. The approach allows not only the computation of the frictional dissipation term in the equations but also to have an insight into the flow structure in the water column during a swash event. The numerical results have been compared with a new set of experiments involving a single dam-break generated swash event. Three different grain sizes, ranging from coarse sand to gravel, have been tested in the laboratory.A sensitivity analysis on the only calibration parameter of the model, the bed roughness, is presented and its optimal value is chosen. The numerically predicted free surface, depth averaged velocity and velocity profiles have been compared with the measured ones. Results are very good in the run-up stage, where also the bottom shear stress is well modelled. In the backwash the frictional energy dissipation is better modelled for the gravel beach than for the coarse sand one. Results show that the simple model accurately predicts the flow parameters during the swash event. Also the velocity profiles are reasonably well predicted, especially during the run-up. (C) 2011 Elsevier B.V. All rights reserved.

KW - Bore-driven swash

KW - Shock capturing schemes

KW - Bottom boundary layer

KW - Bottom shear stress

KW - Momentum integral method

KW - Flow

KW - Bed

KW - Beach

U2 - 10.1016/j.coastaleng.2011.01.004

DO - 10.1016/j.coastaleng.2011.01.004

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JO - Coastal Engineering

JF - Coastal Engineering

IS - 6

ER -