Large Eddy Simulation of an Outflow butterfly valve
Bibliographic record
Abstract
The present study focuses on the aeroacoustic aspects of an outflow butterfly valve that is used to maintain the pressure inside an airplane cabin. When flying at 17,000 ft, an annoying tonal noise has been reported and the flowwithin the valve is transonic. Large Eddy Simulations are performed on different setups in order to understand the noise mechanisms and results are compared with a 2D-rectangular channel butterfly valve representative of the actual geometry. The experimental valve allows performingwall-pressure measurements, Schlieren visualization and far-field noise investigation. Initial LES simulations with second order precision on a relatively coarse mesh have shown difficulties to reproduce the experimental results. Therefore, improvements are made in terms of configuration and numerical scheme leading to the two numerical setups investigated in this paper. Different aerodynamic behaviors, mostly in the shock/boundary layer interaction region, are observed between the two configurations with 0.1D and 0.3D span width. As for the acoustics, far-field computations with FW-H analogy will be compared with experiments for both cases.
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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 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| 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".