The morphodynamics of a swash event on an erodible beach
A high-accuracy numerical solution, coupling one-dimensional shallow water and bed-evolution equations, with, for the first time, a suspended sediment advection equation, thereby including bed and/or suspended load, is used to examine two swash events on an initially plane erodible beach: the event...
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| Format: | Article |
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Cambridge University Press
2015
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| Online Access: | https://eprints.nottingham.ac.uk/35015/ |
| _version_ | 1848794983768784896 |
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| author | Zhu, Fangfang Dodd, Nicholas |
| author_facet | Zhu, Fangfang Dodd, Nicholas |
| author_sort | Zhu, Fangfang |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | A high-accuracy numerical solution, coupling one-dimensional shallow water and bed-evolution equations, with, for the first time, a suspended sediment advection equation, thereby including bed and/or suspended load, is used to examine two swash events on an initially plane erodible beach: the event of Peregrine & Williams (J. Fluid Mech., vol. 440, 2001, pp. 391–399) and that of a solitary wave approaching the beach. Equations are solved by the method of characteristics, and the numerical model is verified. Full coupling of suspended load to beach change for Peregrine & Williams (J. Fluid Mech., vol. 440, 2001, pp. 391–399) yields only slightly altered swash flows, depending on beach mobility and sediment response time; a series of similar final beach change patterns results for different beach mobilities. Suspended- and bed-load transport have distinct morphodynamical signatures. For the solitary wave a backwash bore is created (Hibberd & Peregrine, J. Fluid Mech., vol. 95, 1979, pp. 323–345). This morphodynamical bore propagates offshore initially, and leads to the creation of a beach bed step (Larson & Sunamura, J. Sedimentary Petrology, vol. 63, 1993, pp. 495–500), primarily due to bed-load transport. Its height is directly related to bed-load mobility, and also depends strongly on the bed friction coefficient. The shock dynamics of this bed step is explained and illustrated. Bed- and suspended-load mobilities are quantified using field data, and an attempt is made to relate predictions to measurements of single swash events on a natural beach. Average predicted bed change magnitudes across the swash are of the order of 2 mm, with maximum bed changes of up to approximately 10 cm at the bed step. |
| first_indexed | 2025-11-14T19:24:52Z |
| format | Article |
| id | nottingham-35015 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:24:52Z |
| publishDate | 2015 |
| publisher | Cambridge University Press |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-350152020-05-04T20:10:24Z https://eprints.nottingham.ac.uk/35015/ The morphodynamics of a swash event on an erodible beach Zhu, Fangfang Dodd, Nicholas A high-accuracy numerical solution, coupling one-dimensional shallow water and bed-evolution equations, with, for the first time, a suspended sediment advection equation, thereby including bed and/or suspended load, is used to examine two swash events on an initially plane erodible beach: the event of Peregrine & Williams (J. Fluid Mech., vol. 440, 2001, pp. 391–399) and that of a solitary wave approaching the beach. Equations are solved by the method of characteristics, and the numerical model is verified. Full coupling of suspended load to beach change for Peregrine & Williams (J. Fluid Mech., vol. 440, 2001, pp. 391–399) yields only slightly altered swash flows, depending on beach mobility and sediment response time; a series of similar final beach change patterns results for different beach mobilities. Suspended- and bed-load transport have distinct morphodynamical signatures. For the solitary wave a backwash bore is created (Hibberd & Peregrine, J. Fluid Mech., vol. 95, 1979, pp. 323–345). This morphodynamical bore propagates offshore initially, and leads to the creation of a beach bed step (Larson & Sunamura, J. Sedimentary Petrology, vol. 63, 1993, pp. 495–500), primarily due to bed-load transport. Its height is directly related to bed-load mobility, and also depends strongly on the bed friction coefficient. The shock dynamics of this bed step is explained and illustrated. Bed- and suspended-load mobilities are quantified using field data, and an attempt is made to relate predictions to measurements of single swash events on a natural beach. Average predicted bed change magnitudes across the swash are of the order of 2 mm, with maximum bed changes of up to approximately 10 cm at the bed step. Cambridge University Press 2015-01 Article PeerReviewed Zhu, Fangfang and Dodd, Nicholas (2015) The morphodynamics of a swash event on an erodible beach. Journal of Fluid Mechanics, 762 . pp. 110-140. ISSN 1469-7645 coastal engineering sediment transport shallow water flows http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=9444627&fileId=S0022112014006107 doi:10.1017/jfm.2014.610 doi:10.1017/jfm.2014.610 |
| spellingShingle | coastal engineering sediment transport shallow water flows Zhu, Fangfang Dodd, Nicholas The morphodynamics of a swash event on an erodible beach |
| title | The morphodynamics of a swash event on an erodible beach |
| title_full | The morphodynamics of a swash event on an erodible beach |
| title_fullStr | The morphodynamics of a swash event on an erodible beach |
| title_full_unstemmed | The morphodynamics of a swash event on an erodible beach |
| title_short | The morphodynamics of a swash event on an erodible beach |
| title_sort | morphodynamics of a swash event on an erodible beach |
| topic | coastal engineering sediment transport shallow water flows |
| url | https://eprints.nottingham.ac.uk/35015/ https://eprints.nottingham.ac.uk/35015/ https://eprints.nottingham.ac.uk/35015/ |