STATISTICS OF TURBULENT AND LAMINARIZING FLOW IN A CIRCULAR PIPE WITH A GRADUAL EXPANSION
Bibliographic record
Abstract
Direct numerical simulations of turbulent flow in an axisymmetric pipe with a gradual expansion have been performed for a Reynolds number of 5300 based on the inlet pipe diameter and bulk velocity in order to investigate the effect of a gradual expansion on the flow structure, with special focus on the recirculation and laminarization of the flow downstream of the expansion. An annular ribbed turbolator is used in conjunction with a periodic flow mapping approach to produce fully-developed turbulent flow conditions upstream of the gradual expansion. A turbulent free shear layer initiated at the start of the sudden expansion develops from the flow separation and then reattaches to the pipe wall downstream of the expansion. Following reattachment, the turbulent flow laminarizes as the strength and size of vortical structures gradually diminish. The laminarization process is described in terms of the evolution of the Reynolds stress tensor in the turbulent and laminarizing regions, morphometrically in terms of the evolution of coherent vortical structures, and mechanistically through analysis of the budgets of the vorticity transport equation.
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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 | 0.001 |
| 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 | 0.000 | 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".