Supersonic jet noise and screech tone suppression using cross-wire
Bibliographic record
Abstract
This experimental investigation is aimed at assessing how the introduction of a cross-wire at the exit of a CD nozzle influences the performance of a supersonic nozzle. The study focuses on cold air jets generated by De Laval nozzles equipped with cross-wires and baseline configurations, particularly at design Mach numbers of 1.5 and 1.75. The investigation involves collecting measurements from the noise field emitted by the cross-wire nozzle with a 2% obstruction at the exit. This passive control approach effectively reduces the occurrence of screech tones in both over-expanded and under-expanded conditions in the azimuthal plane at appropriate operating pressures. Various acoustic parameters, including sound pressure levels (SPL), Strouhal numbers, and the overall sound pressure level spectra (OASPL) are recorded. Schlieren imaging captures images of shock cell patterns, illustrating the impact of shock-associated noise. In comparison to a baseline nozzle, the results demonstrate that a CD nozzle equipped with a cross-wire proves to be a proficient screech tone suppressor, leading to an average reduction of up to 5 dB in OASPL in under-expanded and over-expanded scenarios.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 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".