Effect of Rotor Shielding on Fan-Outlet Guide Vanes Broadband Noise Prediction
Bibliographic record
Abstract
An analytical model for the rotor–stator broadband noise is improved by accounting for the rotor acoustic shielding. Both the analytical models for the stator broadband noise and for the rotor scattering are strip-theory approaches based on previously published formulations of the three-dimensional unsteady blade loading for a rectilinear cascade. Specific treatment is introduced to address the behavior around the cut on frequency of the duct modes both in the noise generation and in the noise scattering. A simple effect of the swirl between the rotor and the stator is considered using a Doppler shift in frequency. The power spectral density of the acoustic power and the sound pressure level at the duct wall are studied for the NASA source diagnostic test fan rig. The separate effects of the shielding by a cascade of the rotation of the rotor and of the swirl are investigated. Corotating modes dominate in the inlet. The rotor shielding decreases the acoustic power at intermediate frequencies but increases it at higher frequencies because of the frequency scattering and of the scattering in radial mode orders, which does not exist in a fully rectilinear model. The swirl has a strong effect that must be included.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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".