Modeling of acoustic lined duct with and without grazing air flow by an analytical method
Bibliographic record
Abstract
An analytical method is proposed to characterize the sound acoustic transmission in a rectangular lined duct with and without grazing air flow. The acoustic wave number in the duct is determined using Taylor series expansion. The proposed method is validated by comparison with a finite element method in grazing air flow environment and experimental measurements at grazing sound incidence for the case with no flow. Excellent agreement is found in both configurations. The proposed method is used for sensitivity analysis of acoustic duct lined with micro perforated panel absorber in order to evaluate the impacts of the inputs parameters on the transmission loss of the duct. It is shown for a constant sound pressure level that the transmission loss of the duct is very sensitive to the cavity depth of the absorber while the resonance of the transmission at high sound pressure level is controlled by the perforation ratio of the panel. The effects of the perforation diameter and the plate thickness are negligible for higher pressure excitation and the impact of the sound pressure level on the transmission is preponderant.
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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) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".