CFD Simulation of Air–Water Interactions in Rapidly Filling Horizontal Pipe with Entrapped Air
Bibliographic record
Abstract
One-dimensional mathematical models have been developed in order to predict pressure transients for pipes containing entrapped air undergoing rapid filling. A common hypothesis was adopted in these models, as there exists a distinct vertical air-water interface throughout the filling process. The limitation on the assumption becomes significant for pipes with large diameter, where the filling front undergoes notable deformation due to density difference and gravity effects. This study modeled air-water interactions in a horizontal pipe over rapid filling processes, by using the compressibleInterFoam solver of OpenFOAM. Both empty and partially filled pipe filling cases were simulated and compared with rigid-column models. Comprehensive analyses are presented, including detailed velocity profile, pressure distribution, temperature variation of entrapped air, and interface evolution. The results indicate that the transient water flow is analogous to water hammer flow and that the contribution of air-water mixing on the pressure oscillation damping is considerable. The findings are helpful to better understand the physics of the flow and to improve numerical models.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 teacher head, 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".