Effect of Momentum Injection On Drag Reduction of a Barge-like Structure
Bibliographic record
Abstract
Using a rectangular prism with a square cross-section and an aspect ratio of 2, this paper studies the effect of the Moving Surface Boundary-layer Control (MSBC) on the fluid dynamics of a barge-like structure. Two rotating cylinders forming vertical edges of the upstream square face provided the momentum injection. Wind tunnel results at a subcritical Reynolds number of 5×105 are complemented by the tow-tank experiments. Results suggest a significant effect of the MSBC on both pressure distribution and forces acting on the barge. In general, the momentum injection leads to a delay in the boundary-layer separation, hence a reduction in the pressure drag. For the present case, wind tunnel results showed a reduction in the drag coefficient of around 24%, while the tow-tank study suggested a decrease of up to 28% for a Froude number of 0.18. It is important to point out that the MSBC is essentially a semipassive process. The rotating elements are hollow cylinders, and the power required in overcoming the bearing friction as well as fluid resistance is rather small. Results suggest that for an input of 1 W, there is at least an 8 W reduction in power due to the decrease in drag. A brief video is available.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| 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) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".