Optimization of Controlled Jets in Crossflow
Bibliographic record
Abstract
The controlled acoustical excitation of a round gas jet injected transversely into crossflow, is studied. Use of an open-loop, or feedforward, controller in the experiments allowed for straightforward comparisons to be made among jet responses to different conditions of acoustic excitation of jet fluid. It was found that, for a variety of excitation frequencies, optimal temporal pulse widths during square wave excitation produced clear and distinctly rolled-up vortical structures as well as increased jet penetration into the crossflow forjet-to-crossflow velocity ratios of 2.6 and 4.0. In some cases, application of forcing frequencies corresponding to subharmonics of the upstream shear layer mode for the unforced transverse jet also produced increased jet penetration, coincident with deeply penetrating, distinct vortical structures in the jet. In other instances, merely exciting at the optimal pulse width and at a low excitation frequency (in comparison to the unforced transverse jet shear layer frequency) yielded the best jet penetration and spread. These results on optimization may be interpreted in terms of a universal timescale associated with vortex ring formation and propagation.
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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) | 0.001 | 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 | 0.001 | 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".