Large-Eddy Simulation and Broadband Acoustic Prediction of a Helicopter Rotor in Forward Flight
Bibliographic record
Abstract
A compressible large-eddy simulation (LES) is performed on an helicopter rotor in forward flight in order to compare with wind-tunnel measurements and previous similar simulations in hover. The rotor is the 1/4th scale UH-1 helicopter rotor composed of two blades with a Reynolds number based on chord and tangential tip velocity of 2.27 × 106 and a tip tangential mach number of 0.73. At the inlet, both an advancing and descending velocities are imposed to mimic approach. The resulting flow field is first obtained by an unsteady Reynolds-Averaged Navier-Stokes simulation that provides an initialization to the LES. Both simulation results are then coupled with a FfowcsWilliams & Hawkings analogy to compute the noise in the far field. Combined approaches show a very good agreement with experiment over the full audible frequency range. The low to mid-frequency range is dominated by the Blade-Vortex Interaction that is much more parallel in the present case. The high frequency range is mostly caused by broadband turbulence-interaction noise.
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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".