Numerical study of detonation wave propagation modes in annular channels
Bibliographic record
Abstract
Modes of detonation wave propagation in annular channels were investigated numerically by using the adaptive mesh refinement technique. Two-dimensional, reactive Euler equations with a detailed hydrogen/oxygen reaction model were adopted in the computations to simulate the detonation dynamics in the annular geometry. Considering both the decoupling of the detonation wave front and the development of the Mach-stem in reflection, the propagation is divided into unstable and stable propagation modes with different Mach-stem evolutions, namely, a growing, steady, or decaying type. The numerical observations indicate that in the unstable propagation mode, velocity loss and oscillation occur near the inner wall, while the wave front shape and velocity evolution are steadier for the stable propagation mode. The overdriven degree near the outer wall increases as the Mach-stem strength attenuates. The propagation mode diagrams demonstrate that an increase in the initial pressure and wall curvature radius can extend the range of the stable propagation mode, and the Mach-stem is transformed from a growing to steady, and finally a decaying type with the increase in the initial pressure or the decrease in the wall curvature radius to channel width ratio. The limit of wall curvature radius separating the unstable and stable modes is independent of the channel width for the Mach-stem steady and decaying types, while they are positively correlated for the Mach-stem growing type. Finally, a qualitative procedure is proposed to help distinguish different propagation modes based on the formation mechanism of each propagation dynamics.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 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".