Reynolds number effects on the fine structure of uniformly sheared turbulence
Bibliographic record
Abstract
This study is an experimental investigation of the fine structure of uniformly sheared turbulence within the framework of Kolmogorov’s local isotropy theory. The fine structure was invoked from statistics of derivatives and differences of the streamwise velocity, in both the streamwise and transverse directions, for turbulence Reynolds numbers Reλ between 140 and 660. The streamwise derivative had a pdf with highly asymmetrical, stretched tails, which became more pronounced as Reλ increased. Its skewness grew slowly with Reλ, while its flatness increased at a higher rate, in conformity with previous studies. The transverse derivative had a pdf with a tail asymmetry that decreased as Reλ increased. Its skewness was positive and decreased from about 0.70 at Reλ=140 to about 0.34 at Reλ=660, while its flatness had values near 8.0 and increased only slightly with Reλ. The pdf and flatnesses of velocity differences suggested that intermittency in the inertial spectral range increased with a decreasing separation distance and increasing Reλ. Structure functions up to fourth order were compatible with Kolmogorov’s hypotheses, while the sixth-order structure functions required some correction.
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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 | 0.003 |
| 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 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| 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".