Analysis and Simulation of a Detonation Bounded by a Low Impedance Gas
Bibliographic record
Abstract
The wave speed and structure of a detonation that is bounded by a low impedance layer, such that a precursor shock may move ahead of the detonation, is studied analytically. This situation may occur when a detonation propagates in a layer bounded by combustion products, a scenario that is relevant to conditions occurring in rotating detonation engines. Depending on the acoustic impedance ratio between the combustion products and the reactive gases ahead of the detonation, the wave interaction at the interface can differ significantly. For high acoustic impedance ratios, an oblique shock is transmitted behind the detonation. Conversely, at low impedance ratios, a precursor shock wave propagates in the nonreactive layer ahead of the detonation, significantly altering the flow dynamics. The analytical model presented utilizes a two-layer approach derived by Mitrofanov (Acta Astronaut. 3:995-1004, 1976) to find the detonation velocity. The interaction at the interface between the detonation and the inert layer is characterized using shock, detonation, and expansion polars, complemented by geometrical relations analogous to those in overexpanded nozzle flows. Two distinct wave configurations are identified using polar diagrams, with their onset predicted analytically and validated numerically. Computational Fluid Dynamics (CFD) simulations are employed to compare against the analytical predictions, demonstrating strong agreement.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".