ANALYTICAL MODEL OF SOUND TRANSMISSION THROUGH ORTHOTROPIC DOUBLE WALLED CYLINDERICAL SHELLS
Bibliographic record
Abstract
Due to the high levels of noise into the modern launchers, the structural-acoustic coupling problem is an important subject in the area of vibro-acoustic analysis. In this paper, analytical study is conducted on oblique plane wave incident upon a flexible orthotropic double-walled thin cylindrical shell to understand the characteristic of sound transmission. External and internal fluid media surround the shells and there is fluid (air) in the annular space between them. A uniform flow moves with a constant velocity in the external fluid medium. The wave equations represent the fluid media and the Sanders equations describe the motions of the two shells. On the internal and external shell surfaces, the equations of fluid-structure interaction are considered. An exact solution is obtained by solving the classical shell equations and acoustic wave equations simultaneously. As, the pressure and displacement terms are expressed in infinite series form, an iterative procedure is constructed in each frequency. This convergence algorithm presents the advantage of best accuracy. Transmission losses (TLs) obtained from numerical solution are compared with those of other authors. Eventually, the numerical results are used to show the effects of, orthotropy ratio, geometrical properties, air gap specifications, Mach number, material and fluid properties.
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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 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".