A tornado-based laboratory model for Keplerian flows
Bibliographic record
Abstract
ABSTRACT We introduce a laboratory experiment utilizing a water tornado to model Keplerian flows, which are relevant to astrophysical accretion discs. The tornado is generated by opposing water jet streams, creating a hyperbolic free surface that acts like a gravitational potential. Key findings demonstrate that tracer particles show a Keplerian rotation profile with $\Omega \propto r^{-3/2}$ and conserved area speed, aligning with Kepler’s third and second law. The experiment enables the determination of dimensionless quantities such as the flow’s Reynolds number and the tracer particles’ Stokes numbers. The effective Reynolds numbers measured, $\mathrm{Re} = 2 \times 10^5$, are within the range for turbulent protoplanetary discs of $\mathrm{Re} = 10^3$–$10^5$. The recovered Stokes numbers (ranging between 10$^{-2}$ and 10$^{-1}$) show excellent agreement with the major dust component. Furthermore, the set-up’s advantages include its ability to achieve a large ratio between inner and outer radii, allowing for the study of global dynamics instead of local shear flows. It is diagnostically very accessible and geometrically flexible. The experiment opens a new avenue for studying the interaction between dust and gas in protoplanetary discs, relevant to grain growth and planet formation.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".