Investigation of mechanisms governing turbulence-induced initiation of motion in non-cohesive sediment layers
Bibliographic record
Abstract
ABSTRACT In this research, experiments were conducted to quantify how turbulence affects the initiation of three groups of quartz sands with consecutively increasing particle diameter. In the experimental setup, controlled acrylic paddles, a camera equipped with a macro lens and an acoustic Doppler velocimeter (ADV) were applied to generate turbulence, to record the precise moments of sediment initiation and to measure flow velocity and turbulence properties, respectively. Two categories of sediment initiation were characterized: sliding and suspension, with the onset of suspension occurring at higher turbulence intensities when compared to sliding. In addition, turbulent kinetic energy and Reynolds shear stress were identified as the most critical parameters for sediment initiation. The results suggested that the first and third groups required higher turbulent levels compared with the second group, due to variations in particle size and weight. Quadrant analysis showed that sliding events predominantly occurred during ejection and up-acceleration phases, while suspension events were mostly associated with ejections, which confirmed that initiation tends to occur in specific turbulent structures. Last, a single dimensionless parameter (J) that expresses the probability of sediment initiation under turbulent flow conditions, based on the ratio of turbulent kinetic energy to critical incipient shear stress, was proposed.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| 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".