How seams alter boundary layer separation points on baseballs
Bibliographic record
Abstract
Abstract In this study, we examine the location of boundary layer separation for air flowing over baseballs that are not spinning and the extent to which these locations are modified by seams (i.e. The Seam Shifted Wake). This is an extension of an earlier study based upon a much smaller data set. In both studies, the baseball is propelled in room air and the flow around the ball is measured with particle image velocimetry. In this study, we avoid the assumption that the results are deterministic. We find that the separation location depends on 1) the boundary layer state (whether laminar or turbulent) as well as 2) seams near the separation location. The boundary layer state, in turn, is found to depend on the Reynolds number, the height of the seams (which vary from one ball to the next), and, most importantly, whether a seam lies downstream of the stagnation point and in a region where the favorable pressure gradient is not so strong as to damp the disturbance from the seam. As a result, the separation becomes dependent on the location of two seams, one on the front of the ball and another near the separation location.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".