Vortex shedding control on a bare cylinder using hexagonal perforated outer cylinder
Bibliographic record
Abstract
The aim of the study is to observe the effect of outer hexagonal perforated cylinder surrounding an inner cylinder on vortex structure behind bluff body. Vortex shedding characteristics from bluff body are experimentally studied by particle image velocimetry (PIV) in deep water. The inner cylinder had seven different diameters (Di), varied from 30 to 90 mm with an increment of 10 mm and the hexagonally perforated outer cylinder placed outside of the inner cylinder was used as a control element. Experiments were carried out with six perforated cylinders with a diameters of 100 mm (Do) and six porosities, β, with hole diameter 10 mm. The porosity, β, and diameter ratio, Di/Do, had substantial effect on the flow characteristics behind the cylinder. For the range of diameter ratios of 0.3 ≤ Di/Do ≤ 0.5 the optimum porosity that controls the flow structure is found to be β = 0.6. For 0.6 ≤ Di/Do ≤ 0.7 it is β = 0.5 and β = 0.4 for 0.8 ≤ Di/Do ≤ 0.9. With increasing diameter ratio, Di/Do, peak magnitude locations of Reynolds shear stress, [Formula: see text], and turbulence kinetic energy approach the inner outer cylinder system slightly. For all diameter ratios, β = 0.6 is the most effective porosity ratio.
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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 | 0.000 |
| 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 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".