The effect of high frequency vortex generator on the acoustic resonance excitation in shallow rectangular cavities
Bibliographic record
Abstract
The flow-excited acoustic resonance in shallow rectangular cavities can be a source of severe noise and/or excessive vibration. This phenomenon is excited when one of the acoustic modes in the accommodating enclosure is coupled with the flow instabilities resulting from the shear layer formation at the cavity mouth. In this study the effect of placing a high frequency vortex generator (control cylinder) in vicinity of the upstream edge of the cavity on the acoustic resonance excitation is experimentally and numerically investigated. The effectiveness of the passive method is studied by investigating different cylinder diameters and locations on both horizontal and vertical directions. The study included two cavities with different aspect ratios (L/D=1.0 and L/D=1.67, L: cavity length, D: cavity depth) to address the effectiveness of the method with respect to the cavity depth. The method is investigated in flow with Mach number up to 0.45 and found to be effective in suppressing the acoustic resonance excitation. All the different configurations investigated are compared to the base case which is the bare cavity with no cylinder attached. It is observed that using the optimum cylinder location and diameter can be very effective and able to keep the acoustic pressure below 140 Pa, compared to the base case with values exceeding 2000 Pa. To further understand the interaction between the cylinder vortex shedding and the shear layer at the cavity mouth and the influence on the shear layer thickness, a 2D numerical simulation using a detached eddy simulation models has been carried out and compared to the experimental results.
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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 | 0.000 | 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".