Turbulent transition of thermocapillary flow induced by water evaporation
Bibliographic record
Abstract
Water has been examined for thermocapillary convection while maintained just outside the mouth of a stainless-steel, conical funnel where it evaporated at different but steady rates. Evaporation at a series of controlled rates was produced by reducing the pressure in the vapor-phase to different but constant values while maintaining the temperature of the water a few millimeters below the interface at 3.56+/-0.03 degrees C in each case. Since water has its maximum density at 4 degrees C, these conditions ensured there would be no buoyancy-driven convection. The measured temperature profile along the liquid-vapor interface was found to be approximately axisymmetric and parabolic with its minimum on the center line and maximum at the periphery. The thermocapillary flow rate was determined in two ways: (1) It was calculated from the interfacial temperature gradient measured along the interface. (2) The deflection of a 12.7-microm-diameter, cantilevered probe inserted into the flow was measured and the liquid velocity required to give that deflection determined. The values determined by the two methods agree reasonably. As the vapor-phase pressure was reduced, the thermocapillary flow rate increased until a limiting value was reached. When the pressure was reduced further, certain of the variable relations underwent a bifurcation and the power spectrum of the probe displacement indicated it was a periodic function with frequency locking. These results suggest that thermocapillary flow plays an important role in the energy transport near the interface of evaporating water. In particular, it appears that the subinterface, uniform-temperature layer, reported in earlier studies, results from the mixing produced by the thermocapillary flow. The Stefan boundary condition is often applied to determine the energy flux to an interface where phase change is occurring; however, when there is strong convective flow parallel to the interface, the normal Stefan condition does not give an adequate description of the energy transport.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".