Air thermochemistry in the converging section of de Laval nozzles on hypersonic wind tunnels
Bibliographic record
Abstract
State-to-state simulations of nonequilibrium flow in nozzles are made for a range of reservoir conditions and geometries. The geometry of the converging section and throat has little influence on the thermochemistry of the flow. Higher reservoir pressure and temperature both drive the thermochemistry toward equilibrium. For reservoir temperatures of 1500, 4000, and 7000 K, the flow property that has the largest departure from equilibrium is the N2 vibrational temperature, the O mass fraction, and the N mass fraction, respectively. Even at the lowest reservoir pressure, these departures from equilibrium are only 14%, 8%, and 2% for the 1500, 4000, and 7000 K reservoirs, respectively. The differences in these flow properties at the throat between the nonequilibrium and equilibrium simulations are maintained throughout in the nonequilibrium simulations of the diverging section. Applying the simplification of equilibrium flow in the converging section and around the throat yields almost no observable errors in the vibrational population distributions in the diverging section. The simplification is recommended for most practical intents and purposes, and the current work provides important quantitative information to make informed judgments when applying it.
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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 | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".