The transition from CJ-deflagration to detonation in a square channel
Bibliographic record
Abstract
Experiments were performed in a 7.6 cm square channel to study the transition of a Chapman-Jouguet (CJ) deflagration to detonation in stoichiometric propane-oxygen, hydrogen-oxygen, and acetylene-oxygen with and without argon dilution. The subcritical transmission of a CJ detonation wave through a perforated plate produced a CJ deflagration. High-speed side-view schlieren, end view chemiluminescence visualization, and soot foils were used to identify the location and nature of the deflagration-to-detonation transition (DDT) process. Detonation initiation was categorized as prompt or delayed depending on the effect of the compressible-turbulent flow immediately downstream of the perforated plate. For prompt initiation the transverse waves generated by the decoupled detonation were directly responsible for detonation initiation. The mixture detonation cell structure irregularity played no role in prompt initiation but played a significant role for delayed initiation. For undiluted propane-oxygen progressive strengthening of the transverse waves ultimately led to detonation initiation at the channel walls because of lateral transverse wave collisions. For the argon diluted mixtures that have regular detonation cell structures, detonation initiation typically occurred in the corners, most likely due to flame boundary layer interaction due to the absence of transverse wave collisions at the DDT location. The mechanism for transverse wave amplification was not present for the regular cell structure mixture.
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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".