Tonal Aeroacoustic Sources of a Cambered Airfoil Using Wavelet Beamforming
Bibliographic record
Abstract
At low Reynolds numbers, Re = 1.4 × 10^5 and Re = 1.8 × 10^5 , and low angles of attack α= 0◦ and α = 5◦, the aeroacoustic behaviour of the controlled diffusion (CD) airfoil has been investigated. For these conditions, the airfoil produces tones which are unsteady in nature as found in previous numerical and experimental investigations. Wavelet beamforming is used to investigate the behaviour of the acoustic sources on the pressure and suction sides of the airfoil. In order to improve the spatial resolution of the wavelet beamforming maps a novel technique based on a ρ-PHAT-C generalised cross-correlation approach has been applied. The time-frequency domain study of the aeroacoustic source location on the CD airfoil has found that the dominant acoustic source is on the suction side of the airfoil in between the leading edge and the laminar separation bubble at the trailing edge, quantifying for the first time the actual acoustic feedback loop responsible for the intermittent tones. The unsteadiness in the source position significantly increases with Reynolds number. In the main hump of the acoustic spectra, source behaviour does not change with frequency or presence of a tonal peak.
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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) | 0.001 | 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) | 0.001 | 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".