Effect of Sand Bed Deposits on the Characteristics of Turbulent Flow of Water in Horizontal Annuli
Bibliographic record
Abstract
An experimental program was conducted to investigate turbulent flow of water over the stationary sand bed deposited in horizontal annuli. A large-scale horizontal flow loop equipped with the state-of-the-art particle image velocimetry (PIV) system has been used for the experiments. Experiments were conducted to measure the instantaneous local velocity profiles during turbulent flow and examine the impact of the presence of a stationary sand bed deposits on the local velocity profiles, Reynolds shear stresses and turbulence intensities. Results have shown that the existence of a stationary sand bed causes the volumetric flow to be diverted away from the lower annular gap. Increasing the sand bed height causes further reduction of the volumetric flow rate in the lower annulus. Velocity profiles near the surface of the bed deposits showed a downward shift from the universal law in wall units indicating that the flow is hydraulically rough near the sand bed. The equivalent roughness height varied with flow rates. At flow rates less than the critical flow rate, the Reynolds stress profile near the bed interface had slightly higher peak values than that of the case with no sand bed. At the critical flow rate, however, the peak Reynolds stress values for the flow over the sand bed was lower than that of the case with no bed. This behavior is attributed to the bed load transport of sand particles at the critical flow rate.
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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 | 0.000 | 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".