Three-dimensional numerical simulation of flow around stream deflectors: The effect of obstruction angle and length
Bibliographic record
Abstract
Fish habitat rehabilitation projects often use paired stream deflectors to increase bed shear stress and maintain a deep pool. Many of these projects have been unsuccessful, mainly because of the lack of knowledge of the complex three-dimensional (3D) flow dynamics created by the deflectors. A 3D numerical model was used to simulate the flow field around stream deflectors in a laboratory flume. Predicted velocities were successfully evaluated against laboratory measurements. Deflectors ranging from contraction ratios of 0.1 -0.35 oriented to flow at angles of 30-150° were used for the simulations. Results show that the upstream dynamic pressure maximum, upstream flow separation distance, upstream downwelling extent, and total downwelling distance all increase with deflector angles. However, local minimum dynamic pressure, nose velocity amplification, downstream downwelling extent, and flow contraction width are maximized at angles closer to 90°. In general, maximum downwelling magnitudes increase for longer deflectors, with the greatest values being found for the 135° deflectors. Increasing the length of the deflectors tends to amplify most of the flow parameters. These findings have important implications for the design of paired deflectors in fish habitat rehabilitation projects where the objective is to maximize the pool size downstream of the obstructions.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.003 | 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 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".