Decaying quasi-two-dimensional turbulence in a rectangular container: laboratory experiments
Bibliographic record
Abstract
Results from a new series of experiments on quasi-two-dimensional turbulence decaying in a rectangular container are presented. The flows are generated electromagnetically in a thin layer of conducting fluid when different configurations of permanent magnets are used to specify the initial characteristics of the flow. The particle image velocimetry method is used to determine the velocity and vorticity fields. These fields are further used to determine the global characteristics of the flow such as the energy, enstrophy and the net angular momentum with respect to the center of the container. The experimental results demonstrate that variations of net angular momentum occur due to the interactions of coherent vortex dipoles/jets with the walls of the container. The variation of the angular momentum of the system, which occurs due to the action of stresses at the solid boundary, can be obtained quantitatively if the initial linear impulse exerted by the magnets on the fluid is known. An analysis of external forces and torques allows one to predict that during the intermediate state of the flow evolution the pattern of the flow will be a rotating quadrupole. The energy spectra of the flow demonstrates upscale energy transfer and corresponding growth of the energy-weighted mean scale. Power law exponents are obtained for both the low and high wave number regions of the spectra. Growth of the Reynolds number of the flow was observed during the intermediate phase of the flow evolution.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| 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 | 0.000 | 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".