Eulerian simulations of oscillating airfoils in power extraction regime
Bibliographic record
Abstract
A wing that is both heaving and pitching simultaneously may extract energy from an oncoming flow, thus acting as a turbine.The theoretical performance of such a concept is investigated here through unsteady, two-dimensional laminar flow simulations using the finite volume, commercial CFD code FLUENT TM .Computations are performed in the heaving reference frame of the airfoil, thus leaving only the pitching motion of the airfoil to be dealt with through a rigid-body mesh rotation and a circular, non-conformal sliding interface.This approach offers the benefit of second order time accurate simulations.For a NACA 0015 airfoil at a Reynolds number of Re = 1 100, a heaving amplitude of one chord (H 0 = c), and a pitching axis at the third chord (x p = c/3), we present a mapping of power extraction efficiency in the frequency and pitching amplitude domain: 0 < fc/U ∞ < 0.25 and 0 < θ 0 < 90 • .Remarkably, efficiency as high as 34% is observed as well as a large parametric region above θ 0 > 55 • of better than 20% results.Impact of varying some of the fixed parameters is also addressed.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".