Experimental investigation of the wake dynamics for a NACA0012 airfoil with a cut-in serrated trailing-edge
Bibliographic record
Abstract
An experimental investigation of the unsteady dynamics in the wake of a NACA0012 (National Advisory Committee for Aeronautics) airfoil with a narrow-angle cut-in serrated trailing-edge is presented. Time-resolved planar particle image velocimetry (PIV) has been performed in the wake region of the airfoil both with and without serrations at a Reynolds number of 78 000. The boundary layers on both sides of the airfoil surface are tripped and the angle of attack is held fixed at zero. Spectral analysis of the PIV results shows that the trailing-edge serrations are linked to increased velocity fluctuations in the wake region which are centered on a non-dimensional frequency range of fc/U∞≈3−5. Proper orthogonal decomposition (POD) is utilized to analyze the spatiotemporal characteristics of the most dominant structures in the wake. Three POD mode pairs identified in the serrated airfoil wake flow are described in detail in two different PIV measurement planes passing through the tip and root of the serrations. Overall, the serrations substantially increase the turbulent kinetic energy in the wake and concentrate this energy within the three identified mode pairs. Spectral analysis of the temporal coefficient signals pertaining to the three mode pairs shows energy concentrated within the frequency band of increased velocity fluctuations identified in the wake region. POD-based reconstruction unfolded a von Kármán-like vortex shedding from the truncated part of the airfoil with fc/U∞≈3.7, which is primarily v-fluctuation driven, convecting through the domain at close to 90% of the free stream velocity.
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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".