Measurements of Separated Flow Transition on a Moderately-Loaded Turbine Airfoil
Bibliographic record
Abstract
This paper describes the measurement of separation, transition and re-attachment of a boundary layer on a moderately-loaded turbine blade at low Reynolds number. Under the conditions of the measurements, the flow on the aft portion of the suction surface experiences laminar separation and transition in a separated shear-layer. As the free shear layer becomes turbulent, the increased entrainment results in reattachment of the boundary layer. This paper compares three different methods of identifying separation, transition and re-attachment of boundary layers. It offers a time-average comparison between pressure, hot-film and hot-wire based methods. The results show that all three methods provide useful results, but that the hot-wire data is superior to the other two methods in providing a picture of the blade-surface flow field. Finally, in the past, hot-films located on the surface of the blade had been used to estimate the location of transition in separated shear-layers. This paper evaluates this practice and highlights its potential and pitfalls through a comparison between hot-wire and hot-film signals. For this comparison, a procedure based on a crosscorrelation parameter relating the velocity field to the quasi-wall-shear-stress values on the surface of the blade was applied. The resulting correlation parameter provides new data that attempts to shed some light on the capacity of laminar, transitional and turbulent boundary layer to propagate information from the external flow to the wall region.
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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 | 0.000 | 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 | 0.001 |
| 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".