On the wake dynamics of wall-mounted helical straked cylinders
Bibliographic record
Abstract
The wake dynamics of wall-mounted circular cylinders with helical strakes are investigated using particle image velocimetry under shallow flow conditions. The helical strakes attached to the cylinder surface have a three-start configuration with a pitch equal to 10d and a height of 0.2d, where d is the cylinder diameter. The influence of strake orientation is explored by positioning the cylinder to align one of the strakes at an angle of 0° or 30° with the streamwise flow at the cylinder-bed junction. In the presence of the strakes, the wakes displayed elevated turbulence levels and reduced mean velocity, which influence the vortex formation length and other wake characteristics. The strakes induce asymmetric behavior across the depth of the flow resulting in the disruption of coherent vortex shedding. When aligned at 0° to the oncoming flow, the strakes increase the Reynolds stresses throughout the flow depth and enhance their diffusion, which can facilitate better wake mixing and momentum exchange. When the strakes are positioned at 30°, the stresses are distributed over a wider region with decreased magnitude. There is a notable increase in energy contributions near the bed for the 0° case as revealed by proper orthogonal decomposition. The spatial modes exhibit a wide range of scales across the flow depth for the straked cylinders.
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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) | 0.000 | 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".