Direct numerical simulation of acoustic reduction using serrated trailing-edge on an isolated airfoil
Bibliographic record
Abstract
Broadband noise produced by the trailing edge of a controlled diffusion (CD) airfoil with a serrated trailing edge in the actual anechoic wind-tunnel test configuration is directly simulated using a Lattice-Boltzmann method at a high Reynolds number of 1.5× 10 typical of actual ventilation systems and low pressure turbomachinery stages. Such an unique simulation resolves both the aerodynamic and acoustic field around the airfoil. The comparison of the airfoil loading, the wall-boundary layer development, and the near-wake flow between the clean and serrated configurations is systematically performed and results are compared with the detailed experimental database available for the clean airfoil. A slight lift reduction is found with the serrations near the trailing-edge. The turbulent wallpressure fluctuations on the airfoil suction-side are only slightly modified. Because of the serrations the pressure and suction side boundary layer flows merge differently than in the clean case, modifying the near-wake evolution with larger coherent hairpin structures. The slight vortex shedding observed on the pressure side of the clean airfoil is also suppressed. Finally a noise reduction is captured between 1000 and 3500 Hz in all direction except in the wake direction where a slight noise increase is noticed.
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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 | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".