Coherent structures in uniformly sheared turbulent flow
Bibliographic record
Abstract
Abstract Uniformly sheared turbulent flow has been generated in a water tunnel and its instantaneous structure has been examined using flow visualization and particle image velocimetry. The shear-rate parameter was approximately equal to 13 and the streamwise turbulence Reynolds number was approximately 150. The flow was found to consist of regions with nearly uniform velocity, which were separated by regions of high shear containing large vortices. The concentration of vortices and the distributions of their directions of rotation, strengths, sizes and shapes have been determined. These results demonstrate that horseshoe/hairpin-shaped vortices were prevalent, even though wall effects were negligible in this flow. Both ‘upright’ and ‘inverted’ vortices have been observed, in contrast to turbulent boundary layers, in which only ‘upright’ vortices can be found, suggesting that the presence of the wall may suppress the development of ‘inverted’ structures. Our observations demonstrate that the dominant coherent structures of fully developed uniformly sheared flow are very different from the structures observed in the flow exiting the shear-generating apparatus, which points to an insensitivity of the former to initial effects.
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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) | 0.000 | 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 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".