Measurements of the Effects of Pressure-Gradient History on Separation-Bubble Transition
Bibliographic record
Abstract
In many boundary-layer situations, particularly in turbomachinery, separation-bubble transition occurs at a local pressure gradient that differs significantly from the values further upstream. Additionally, this upstream history changes substantially from case to case, with the transitioning separation bubble occurring at streamwise positions along the blade chord varying from close vicinity of the leading edge to mid-chord. In the case of low free-stream disturbances, development of instability waves prior to separation would clearly vary as a result of these differences in the history of the boundary layer prior to separation. Measurements are presented to document the effects of pressure gradients that a laminar boundary layer experiences prior to separation on the transition process that follows in the separated region. The boundary layer development was measured on a smooth, flat plate upon which streamwise pressure gradients were imposed by a flexible, contoured wall opposite to the test plate. Only low freestream-turbulence levels were considered to isolate the effects of pressure-gradient history on the transition process. Two Reynolds numbers were considered for each pressure-gradient setting. Measured quantities consisted of velocity and turbulence intensity obtained with a single hot-wire, and of surface pressures. Observed variations in transition onset location with changes in pressure-gradient history provide the basis for further development of current transition prediction schemes.
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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".