Choking conditions inside plunging flow dropshafts
Why this work is in the frame
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Bibliographic record
Abstract
Severe rain events can subject our existing drainage systems to capacity. While the conveyance capacity of sewers can be increased by temporarily tolerating a full pipe flow condition, the complex dynamics of water–air mixture occurring in vertical dropshafts can largely restrict the overall conveyance capacity of drainage systems. In this study, the hydraulic performance of plunging flow dropshafts is investigated experimentally with respect to their conveyance capacity. The model dropshaft consisted of an upstream horizontal inflow pipe, a vertical circular shaft, and an outflow pipe discharging to the atmosphere. Five setups were built with D s /D i from 1.0 to 3.0 for the range of drop heights H/D s = 3.0 to 21.0, where D i is the inlet pipe diameter, D s the shaft diameter, and H the drop height. A wide range of discharges up to Q* = 25 was tested, where Q* = Q/(gD i 5 ) (1/2) . Flow patterns recognized within the shaft (free flow, surface roller, plug flow, slug flow, and full pipe flow) help to assess the two stages of choking: the incipient and fully choked state. Criteria to predict choking occurrences were developed experimentally. The flow is considered to reach its conveyance capacity when an incipient choking state is visible. For a typical dropshaft with D s /D i = 2, Q* was found to be approximately 5.
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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) | 0.000 | 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 it