Bibliographic record
Abstract
This paper deals with the classical problem of transmission-reflection and modes conversion due to the presence of acoustic liners in duct.The model consists of an infinite rectangular duct with an unlined and lined section.The approach is based on the modal calculation of the total acoustic sound power in a duct by the determination of the modal coefficients of the transmitted waves at the impedance discontinuity junc tion.For a given propagating mode (plane wave or higher order mode), incident from the rigid duct, the total sound power is calculated in the lined section by summing the acoustic power over all generated modes.The example studied here shows how the conversion affects the nature of the incident mode as a function of the admittance of the liner, frequency and mode number.It also allows for the quantification of the attenuation provided by an acoustic duct liner. SOMMAIRELe recours a des revtements de parois absorbants le long d'un conduit est un moyen naturel de rduire le bruit gnr par des machines tournantes (turboracteurs, circuits de ventilation, etc.).D'un point de vue scientifique, ce contexte pose plusieurs problmes fondamentaux tant sur le plan de la comprhension des phnomnes que sur celui de leur modlisation.Il faut en effet pouvoir prciser les aspects lis la propa gation guide en prsence de parois absorbantes.Cet article s'inscrit dans ce contexte et discute les effets lis la conversion des modes qui est cause par la prsence d'une discontinuit d'impdance en conduit.Pour ce faire, un model de conduit infini tridimensionnel a t tudi ou une partie est traite par un revte ment acoustique.L'approche est base sur un calcul modal de la puissance acoustique en conduit aprs dtermination des coefficients modaux des modes transmis.Pour un mode de propagation donn (ondes planes ou modes suprieures), dans la section rigide du conduit, la puissance acoustique totale est calcule dans la section traite en sommant les puissances des modes gnrs par la discontinuit d'impdance.L'exemple tudi ici montre comment cette conversion affecte la nature du mode incident en fonction de l'impdance du revtement acoustique, de la frquence et du mode.Il permet aussi de calculer l'attnuation apporte par un revtement acoustique en conduit.
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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".