Boundary Layer Tripping for a Simplified Landing Gear Model
Bibliographic record
Abstract
Experimental investigations have been conducted on a simplified model landing gear with the aim of evaluating the effect of boundary layer tripping upon the flow behaviour. The pressure distribution around a single wheel landing gear model has been measured at the University of Toronto Institute for Aerospace Studies (UTIAS) low speed wind tunnel at a Reynolds number of Re = 0.5x10 6 . These measurements identified two pressure plateaus, one on each side of the wheel just aft of the wheel maximum thickness, indicating possible separation bubbles. Surface visualisations using the china clay method also show the presence of a dual bump footprint at these locations. With the application of zigzag boundary layer tripping, these pressure plateaus were removed thereby returning the pressure distribution around the wheel circumference to the more parabolic profile seen at higher Reynolds numbers by other researchers. Further studies were also performed in the UTIAS recirculating water tunnel at a lower Reynolds number of Re = 0.2 x 10 6 . Within the water tunnel, pressure measurements on the untripped wheel also contained similar pressure plateaus at the same wheel locations. Using time resolved PIV measurements, these pressure plateaus were identified to be caused by an unsteady recirculation bubble, exhibiting growth and bursting behaviour. Four varieties of boundary layer trip devices (zigzag, wire, roughness and CAD-cut dots) were then investigated for their impact on the flow. Certain sizes of wire and roughness trips were shown to remove these pressure plateaus from the pressure measurements, with PIV confirming that the unsteady separation bubble behaviour was also greatly diminished. Pressure measurements of the zigzag trips identified a partial removal of these plateaus, with the related PIV observations indicating both a reduction in size and a shift in the bubble formation location to a further aft position on the wheel rear. Whereas the CAD-cut dots were not observed to change the flow around the wheel significantly.
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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 | 0.002 | 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 | 0.001 | 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".