Threshold criteria for incipient sediment motion on an inclined bedform in the presence of oscillating-grid turbulence
Here, we report laboratory experiments to investigate the threshold criteria for incipient sediment motion in the presence of oscillating-grid turbulence, with the bed slope inclined at angles between the horizontal and the repose limit for the sediment. A set of nine mono-disperse sediment types wa...
| Main Authors: | , |
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| Format: | Article |
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American Institute of Physics
2013
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| Online Access: | https://eprints.nottingham.ac.uk/33547/ |
| _version_ | 1848794653821763584 |
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| author | Wan Mohtar, Wan Hanna Melini Munro, Richard J. |
| author_facet | Wan Mohtar, Wan Hanna Melini Munro, Richard J. |
| author_sort | Wan Mohtar, Wan Hanna Melini |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | Here, we report laboratory experiments to investigate the threshold criteria for incipient sediment motion in the presence of oscillating-grid turbulence, with the bed slope inclined at angles between the horizontal and the repose limit for the sediment. A set of nine mono-disperse sediment types was used with size ranges normally associated with either the hydraulically-smooth or transitional regimes. Measurements of the (turbulent) fluid velocity field, in the region between the grid and bedform's surface, were obtained using two-dimensional particle imaging velocimetry. Statistical analysis of the velocity data showed that the turbulence had a anisotropic structure, due to the net transfer of energy from the normal to the tangential velocity components in the near-bed region, and that the fluctuations were dominant compared to the secondary mean flow. The sediment threshold criteria for horizontal bedforms were compared with, and found to be in good qualitative agreement with the standard Shields curve. For non-horizontal bedforms, the bed mobility was found to increase with increasing bed slope, and the threshold criteria were compared with previously-reported theoretical models, based on simple force-balance arguments. |
| first_indexed | 2025-11-14T19:19:37Z |
| format | Article |
| id | nottingham-33547 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:19:37Z |
| publishDate | 2013 |
| publisher | American Institute of Physics |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-335472020-05-04T16:35:31Z https://eprints.nottingham.ac.uk/33547/ Threshold criteria for incipient sediment motion on an inclined bedform in the presence of oscillating-grid turbulence Wan Mohtar, Wan Hanna Melini Munro, Richard J. Here, we report laboratory experiments to investigate the threshold criteria for incipient sediment motion in the presence of oscillating-grid turbulence, with the bed slope inclined at angles between the horizontal and the repose limit for the sediment. A set of nine mono-disperse sediment types was used with size ranges normally associated with either the hydraulically-smooth or transitional regimes. Measurements of the (turbulent) fluid velocity field, in the region between the grid and bedform's surface, were obtained using two-dimensional particle imaging velocimetry. Statistical analysis of the velocity data showed that the turbulence had a anisotropic structure, due to the net transfer of energy from the normal to the tangential velocity components in the near-bed region, and that the fluctuations were dominant compared to the secondary mean flow. The sediment threshold criteria for horizontal bedforms were compared with, and found to be in good qualitative agreement with the standard Shields curve. For non-horizontal bedforms, the bed mobility was found to increase with increasing bed slope, and the threshold criteria were compared with previously-reported theoretical models, based on simple force-balance arguments. American Institute of Physics 2013-01-14 Article PeerReviewed Wan Mohtar, Wan Hanna Melini and Munro, Richard J. (2013) Threshold criteria for incipient sediment motion on an inclined bedform in the presence of oscillating-grid turbulence. Physics of Fluids, 25 (1). ISSN 1070-6631 http://dx.doi.org/10.1063/1.4774341 doi:10.1063/1.4774341 doi:10.1063/1.4774341 |
| spellingShingle | Wan Mohtar, Wan Hanna Melini Munro, Richard J. Threshold criteria for incipient sediment motion on an inclined bedform in the presence of oscillating-grid turbulence |
| title | Threshold criteria for incipient sediment motion on an inclined bedform in the presence of oscillating-grid turbulence |
| title_full | Threshold criteria for incipient sediment motion on an inclined bedform in the presence of oscillating-grid turbulence |
| title_fullStr | Threshold criteria for incipient sediment motion on an inclined bedform in the presence of oscillating-grid turbulence |
| title_full_unstemmed | Threshold criteria for incipient sediment motion on an inclined bedform in the presence of oscillating-grid turbulence |
| title_short | Threshold criteria for incipient sediment motion on an inclined bedform in the presence of oscillating-grid turbulence |
| title_sort | threshold criteria for incipient sediment motion on an inclined bedform in the presence of oscillating-grid turbulence |
| url | https://eprints.nottingham.ac.uk/33547/ https://eprints.nottingham.ac.uk/33547/ https://eprints.nottingham.ac.uk/33547/ |