Dynamic stall induced by a periodic transverse gust of an airfoil at transitional Reynolds numbers
Bibliographic record
Abstract
The aerodynamic response of an airfoil to periodic (harmonic) transverse gusts at transitional Reynolds numbers (Rec≈105) is investigated experimentally in a low-speed wind tunnel, with particular emphasis on gust-induced dynamic stall. A gust generator employing two motor-driven vanes produces periodic transverse gusts. The downstream flow is characterized under both static and dynamic conditions before mounting a stationary test wing. The wing, equipped with an internal six-component balance at mid-span, is first examined in uniform freestream, and then under gust excitation across pre- and post-stall regimes. In the pre-stall regime, the measured lift matches linear predictions from Küssner's and Sears functions. In the post-stall regime, the effective angle of attack, defined as the geometric wing angle plus the gust angle, enables qualitative comparison with pitch-induced dynamic stall. The gust angle is defined by treating the transverse gust as an equivalent camber-induced downwash and computing it from a thin-airfoil downwash integral. Around a static stall, transverse gusts drive the wing into deep post-stall, where pronounced nonlinear effects emerge, including lift enhancement and hysteresis in both lift and moment. These behaviors are attributed to alternating upwash and downwash induced by transverse gusts, analogous to the upstroke and downstroke hysteresis observed in pitch-induced dynamic stall. At a comparable reduced frequency, the similarity of lift and moment responses highlights an analogy between the gust-induced and classical pitch-induced dynamic stalls. Parametric variations in gust amplitude and Reynolds number further delineate the dynamics. The influence of flow transition is revealed by mounting a leading-edge transition strip under both uniform freestream and gusty conditions.
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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 | 0.000 |
| 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) | 0.001 | 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".