TURBULENT VORTEX SHEDDING FROM A DUAL-STEP CYLINDER: INFLUENCE OF DIAMETER RATIO AND ASPECT RATIO
Bibliographic record
Abstract
In the present study, the influence of aspect ratio (L/D) and diameter ratio (D/d) on the flow development past a dual-step cylinder is investigated experimentally for ReD = 2100, 1.33 ≤ D/d ≤ 2.67, and 0.2 ≤ L/D ≤ 3. Experiments are carried out in a water flume facility using Laser Doppler Velocimetry (LDV), Particle Image Velocimetry (PIV), and hydrogen bubble flow visualization. The results show that four distinct vortex shedding regimes can be identified based on changes in large cylinder wake development. Depending on the geometrical parameters of the dual-step cylinder, the wake of the large cylinder may involve (i) vortex shedding at a frequency lower than that expected for a uniform cylinder at the same Reynolds number, (ii) irregular shedding, (iii) vortex shedding at a frequency higher than that for a uniform cylinder, and (iv) suppression of large cylinder vortex shedding. Based on the present results and those from previous studies on relevant geometries, a map of wake regimes for a dual-step cylinder has been constructed.
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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) | 0.001 | 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 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".