Acoustic Response of Multiple Shallow Cavities and Prediction of Self-Excited Acoustic Oscillations
Bibliographic record
Abstract
Self-sustaining oscillations of flow over ducted cavities and in corrugated pipes are a known source of tonal noise and excessive vibration in industrial applications. Corrugated pipes can be modeled as a series of axisymmetric cavities. In the current study, the aero-acoustic sources generated by one-, two-, and three-cavity configurations have been experimentally investigated by means of the standing wave method (SWM) for a wide range of Strouhal numbers and acoustic excitation levels. The source strength is found to increase in a nonlinear manner with increasing the number of cavities. Moreover, the self-excited acoustic resonances of the same cavity combinations are investigated. The source characteristics are compared with the observed lock-in range from the self-excited experiments. A prediction model is also developed to utilize the measured source characteristics for estimating the amplitude of the cavities self-sustained oscillations. The self-excited experimental data are used to assess the effect of acoustic absorption at the cavity edges. This absorption is found to be substantial and must be accounted for in the prediction model. When the model is supplemented with appropriate loss coefficients, it predicts fairly well the pulsation amplitude within the resonance lock-in range of the studied multiple cavity configurations.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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".