Active Control of a Self-sustained Pressure Fluctuation due to Flow over a Cavity
Bibliographic record
Abstract
The problem addressed in this paper is to control the self-sustained pressure fluctuations due to flow over a cavity. The vortex sound theory describes how sound can be induced by periodic shedding of discrete vortices at the leading edge and their interaction with the downstream edge after convection across the cavity. The pressure sound generated by the vortex-edge interaction propagates upstream and trigger the vortex shedding upstream of the leading edge. An active device can act on this feedback loop in order to break the reinforcement mechanism, and thus to attenuate the self-sustained pressure fluctuations. The main originality of the presented active device is to use a vibrating surface located at the trailing edge in order to control the volume velocity generated by the interaction of vortex with the wall. The command of the vibrating surface is synchronized with the pressure fluctuations measured at the bottom of the cavity with a microphone. The describing function analysis is used to predict the self-sustained sinusoidal pressure and to explain the action of the active device on the feedback loop. Experimental data were obtained using the system in the test section of an Eiffel type wind-tunnel. The pressure fluctuation spectrum measured in the cavity without and with active control show an attenuation of 20 dB.
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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".