Time response of active sound control with a harmonic acoustic pneumatic source: simulations and experimental results
Bibliographic record
Abstract
Active noise control is studied as a solution to reduce the blade passing frequency tonal noise of turbofans during landing and takeoff. A promising alternative to loudspeakers used as secondary sources is the Harmonic Acoustic Pneumatic Source (HAPS), that has been designed to generate a high harmonic noise level controllable in amplitude and phase using slow time varying signals. The objective is to design, characterize and optimize an active control system capable of following a time varying primary noise. A configuration with a loudspeaker acting as a primary source, a HAPS mounted laterally on a rectangular duct and an error microphone is considered. A first single-input-single-output controller for the case of plane wave control has been tested and allowed a convergence time of about 2 seconds to reach 20 dB attenuation of the acoustic pressure at 440 Hz. The results are consistent with simulations of the system and the convergence time can be explained by the dynamics of the HAPS. This study is a first step towards the objective of performing multimodal active noise control in duct with multiple sources in presence of flow.
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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".