Coherent Structures in the Transition Process of a Laminar Separation Bubble
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Coherent structures formed within the laminar separation bubble on the suction side of a NACA 0018 airfoil at a chord Reynolds number of 100,000 and an angle of attack of 5 deg are investigated experimentally using a combination of surface pressure measurements; time-resolved flow visualization; and time-resolved planar two-component particle image velocimetry. The results show that strongly periodic shear-layer vortices form in the separation bubble due to the amplification of disturbances in the fore portion of the bubble. These structures feature strong spanwise coherence at rollup; however, they deform rapidly upstream of the mean reattachment location. Spanwise undulations in the vortex filaments develop in a nonperiodic fashion, with the spanwise wavelength shown to be approximately two times the streamwise spacing of the shed structures. It is demonstrated that these spanwise deformations lead to regions of local vortex breakup, which expand rapidly as the vortices approach the mean reattachment point. This is associated with a rapid decay of the spanwise coherence length, which reaches a constant minimum value typical of turbulent boundary layers just downstream of mean reattachment. The results demonstrate that the development of shear-layer vortices plays the fundamental role in the formation of the separation bubble, and the later stages of transition are directly related to the breakup of these structures in the aft portion of the separation bubble.
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.
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