Pressure Surges Following Sudden Air Pocket Entrapment in Stormwater Systems
Bibliographic record
Abstract
Stormwater storage tunnels may undergo rapid pipe filling conditions during extreme rain events.Such conditions are relevant as adverse conditions may develop, such as surging due to entrapment and compression of entrapped air pockets.Operational issues such as structural damage, geysering and the return of conveyed water to grade, among others, have been linked to air pocket entrapment.This chapter presents results from the experimental investigations of pressure surges caused by sudden air pocket entrapment.Steady flow was supplied in a pipeline in such a way that pressurized flows existed at the upstream end while the downstream end experienced free surface flow due to free discharge conditions at the downstream end.A combination of flow rates and slopes resulted in several gradually varied flow profiles at the discharge, with various volumes of atmospheric air at the discharge end.By suddenly closing the downstream discharge valve, an air pocket was entrapped and surges were recorded.To emulate conditions in which surge relief is provided during air pocket compression, valve operation also included cases with partial valve obstruction.Among the obtained results, one can notice significantly different surges for cases with and without pressure relief (e.g. with total or partial obstruction), and that the larger the obstruction degree the larger are the surges.Such findings are useful in the development of numerical models to simulate the rapid filling of stormwater tunnels incorporating these findings.
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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 | 0.002 |
| 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 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| 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".