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The present study evaluates the performance of two numerical approaches in estimating non-equilibrium scour patterns around a non-slender square structure subjected to a transient wave, by comparing numerical findings with experimental data. This study also investigates the impact of the structure’s positioning on bed evolution, analyzing configurations where the structure is either attached to the sidewall or positioned at the centerline of the wave flume. The first numerical method treats sediment particles as a distinct continuum phase, directly solving the continuity and momentum equations for both sediment and fluid phases. The second method estimates sediment transport using the quadratic law of bottom shear stress, yielding robust predictions of bed evolution through meticulous calibration and validation. The findings reveal that both methods underestimate vortex-induced near-bed vertical velocities. Deposits formed along vortex trajectories are overestimated by the first method, while the second method satisfactorily predicts the bed evolution beneath these paths. Scour holes caused by wave impingement tend to backfill as the flow intensity diminishes. The second method cannot sufficiently capture this backfilling, whereas the first method adequately reflects the phenomenon. Overall, this study highlights significant variations in the predictive capabilities of both methods in regard to the evolution of non-equilibrium scour at low Keulegan–Carpenter numbers.
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Experimental study of bed evolution around a non-slender square structure under combined solitary wave and steady current actions
This paper presents the findings from the laboratory wave flume experiments designed to investigate the formation and evolution of scour around a non-slender, square vertical structure, under three flow conditions, solitary wave, combined solitary wave and steady following current, and combined solitary wave and steady opposing current. The structure was placed on a sandy berm, either fastened to the flume wall or positioned at the centerline of the flume. For the wave only case, the scour on the seaside edge turned out to be deeper than the one on the leeside regardless of the structure’s position. The analyses showed that the depth, width, volume, and location of the scour were all significantly influenced by the introduction of steady currents. The following current, for example, deepened the seaside scour, while leading to shallower leeside scour holes as a result of the backfilling process. Contrary to the opposing current, which shifted the scour area in the upwave direction, the scour was transported downwave under the effect of the following current. The scour depth was determined to be a function of the structure position and the Keulegan-Carpenter number, whereas the scour width mostly depended on the structure’s position. In this regard, the structure fastened to the wall experienced the widest scour area and the largest volume regardless of the flow condition.
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- Award ID(s):
- 2050798
- PAR ID:
- 10387719
- Date Published:
- Journal Name:
- Ocean engineering
- Volume:
- 266
- ISSN:
- 1873-5258
- Page Range / eLocation ID:
- 112792
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1016/j.oceaneng.2022.112792
