Study on coherent structures in the flow field of single-cell and vortex breakdown tornado-like vortices
Bibliographic record
Abstract
The coherent structures at different height planes within a vortex-breakdown tornado-like flow field are investigated using particle image velocimetry. Proper orthogonal decomposition (POD) of the experimental velocity field reveals that, in the flow field of tornadoes with vortex breakdown, the vortex is a single-cell structure at high altitude, and the main large-scale coherent structure is vortex wandering. At lower altitude, in the plane where vortex breakdown occurs, the coherent motion of vortex size variations intensifies significantly. The mechanisms whereby large-scale coherent motions (vortex wandering and vortex size variations) influence the fluctuating velocity and Reynolds stresses in the vortex flow field within different vortex structures are determined through the low-order reconstruction of modes and analysis of modal stresses. An investigation of numerically synthesized vortex POD modes explains the origins of POD spatial modes for vortex wandering and vortex size variations in single-vortex and vortex-breakdown tornado-like flow fields. Furthermore, by identifying fewer modes in the velocity fields simulated by Burgers' theoretical model, a simplified model capable of representing the fluctuating velocity in single-vortex tornado flow fields is constructed and found to be in good agreement with experimental results.
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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 | 0.001 | 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".