Application of a Zonal K-ε Model on Simulation of Turbulent Mixed Convection
Bibliographic record
Abstract
Fluid flow and heat transfer in a vertical tube under constant heat flux have been studied and effect of buoyancy force on the heat transfer coefficient is investigated. The finite volume method is used to study turbulent flow in both upward and downward directions. For the turbulence modeling, a zonal k-e model is employed and the numerical results are compared with available experimental data. The results of the simulation show that for the downward flow, heat transfer is enhanced and for strong buoyancy force, flow reversal is observed. In contrast, for the heated upward flow, heat transfer can be either impaired or enhanced by the buoyancy force depending on its strength. Partial laminarization is caused by the buoyancy in the case of modest buoyancy force. For the condition of stronger buoyancy force, a sudden decrease in the fully-developed Nusselt number is evident in the experimental data and well predicted by the numerical solution. In general, the quantitative agreement between the numerical results and the experimental data is satisfactory.
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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 | 0.001 |
| 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) | 0.001 | 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".