Dual vortex structure shedding from low aspect ratio, surface-mounted pyramids
Bibliographic record
Abstract
The flow around surface-mounted, square-based pyramids, of apex angles ranging from 5° to 90°, placed in a thin boundary layer with one face normal to the on-coming flow was investigated for Reynolds numbers of 10 000–150 000 using surface pressure measurements and particle image velocimetry as well as oil-film surface-flow patterns. Based on the periodicity of the surface pressure on the pyramid side faces, four distinct shedding regimes were identified: constant local Strouhal number, discrete cellular, low aspect ratio and suppressed. Closer inspection of the low aspect ratio regime indicates that two distinct vortical structures are shed at the same frequency. Vortices are shed alternately from opposing faces in the obstacle base region, while hairpin vortices are shed in-phase and are most easily observed near the tip region of the pyramid. It is further shown that the existence of these structures is consistent with the mean surface-flow topology observed in the wake and side faces of the obstacles.
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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) | 0.001 | 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".