Multi-Property Measurements at High Sampling Rates Using Rayleigh Scattering
Bibliographic record
Abstract
A molecular Rayleigh scattering technique is developed to measure gas velocity, temperature, and density in unseeded gas flows at sampling rates up to 32 kHz. A high-power continuous-wave laser beam is focused at a point in an air flowfield, and Rayleigh scattered light is collected and fiber-optically transmitted to a Fabry-Perot interferometer for spectral analysis. Photomultiplier tubes operated in the photon-counting mode allow highfrequency sampling of the total signal level and the circular interference pattern to provide density, temperature, and velocity measurements. Mean and root-mean-square fluctuation measurements in both an electrically heated jet facility with a 10-mm-diam nozzle and in a hydrogen-combustor-heated-jet facility with a 50.8-mm-diam nozzle at NASA John H. Glenn Research Center at Lewis Field are presented. Measurements are compared with hot-wire anemometry, cold-wire thermometry, and temporally resolved particle image velocimetry to validate the Rayleigh technique.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| 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".