Investigation of a Passive Flow Control Device in an S-Duct Inlet of a Propulsion System With High Subsonic Flow
Bibliographic record
Abstract
S-Ducts have wide application on air vehicles with embedded engines. The complex geometry is known to lead to separation downstream of curved profiles. This paper reports the influences on that flow of passive flow control geometries. In these experiments, stream-wise tubercles were applied in an effort to improve the internal performance of S-duct diffusers, parameters including pressure recovery, distortion and swirl. The test articles were tested with the high subsonic (Ma = 0.8) flow and were manufactured using 3D printing. Stream-wise static pressure and exit-plane total pressure were measured in a test rig using surface pressure taps and a 5-probe rotating rake, respectively; the baseline and variant S-ducts were simulated through computational fluid dynamics. The experiments showed that some subtle improvements to the S-Duct distortion could be achieved through careful selection of tubercle geometry. Generally, the recovered flow downstream of the inner radius of the second bend of the S-duct deteriorated, but overall pressure recovery improved. The simulations were useful in characterizing swirl, whereas experiments were not so equipped. Adjustments to the numerical approaches resulted in reasonable agreement with the experiments.
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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".