Numerical study of bed proximity effects on the wake characteristics of a circular cylinder
Bibliographic record
Abstract
This study investigates the wake flow dynamics, turbulence characteristics, and vortex structures around a cylinder located near a bed at two gap ratios (G/D=0.25 and 0.50) at a Reynolds number of 8000. Using large eddy simulations, the evolution of velocity profiles, Reynolds stresses, and vortex shedding behavior is analyzed to elucidate the influence of bed confinement on wake development. Results reveal that the smaller gap ratio significantly suppresses vortex shedding and shear layer instabilities, leading to a longer recirculation zone and delayed entrainment of ambient fluid compared to the larger gap ratio. In contrast, the larger gap ratio case exhibits a well-defined von Karman vortex street, earlier shear layer transition, and a separated bed shear layer. Reynolds shear stress analysis highlights enhanced momentum transfer in the larger gap ratio case. In contrast, the smaller gap ratio shows stronger shear layer–bed coupling and vortex annihilation near the bed. Horseshoe-like vortices are identified along the cylinder span, forming sporadically through interaction with upstream bed-induced turbulent eddies. The formation and evolution of these horseshoe-like vortices depend strongly on the bed proximity and turbulent boundary layer dynamics. These findings provide critical insights into the complex interaction between confinement, turbulence, and vortex dynamics, with implications for flow control and sediment transport in near-bed bluff body flows.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".