Vortex Shedding of an Airfoil at Low Reynolds Numbers
Bibliographic record
Abstract
Characteristics of airfoil wake vortices in low Reynolds number flows are investigated. The focus of this investigation is the effect of Reynolds number and airfoil thickness on the shedding frequency of these coherent structures. Experiments were conducted on a NACA 0018 airfoil at an angle of attack of 10° for a range of chord Reynolds numbers from 30,000 to 200,000. The experimental conditions were selected to investigate both laminar boundary-layer separation without reattachment and separation-bubble formation as well as to enable a comparison with data from previous studies. The results show that vortex shedding occurs in the airfoil wake for both flow regimes investigated. The dimensionless wake vortex shedding frequency is shown to vary linearly with Reynolds number; however, the slope of the linear fit depends on the shear-layer behavior. When an increase in Reynolds number results in shear-layer reattachment on the upper surface of the airfoil, the wake shedding frequency increases significantly, and the vortical structures become less coherent. The present results are compared with those available for NACA 0012 and NACA 0025 profiles as well as selected bluff bodies. The comparison demonstrates a similar dependence of the dimensionless frequency on the Reynolds number. In the absence of shear-layer reattachment on the upper surface, airfoil wake vortex shedding resembles that of a bluff body; however, the results show a more pronounced effect of the Reynolds number on the Strouhal number for airfoils. Using a frequency scaling based on a characteristic wake length, the data for two different airfoil profiles are shown to collapse on to a universal Strouhal number of approximately 0.18.
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 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 | 0.000 | 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) | 0.001 | 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".