Matrix-free global stability analysis framework for 2D and 3D applications
Bibliographic record
Abstract
View Video Presentation: https://doi.org/10.2514/6.2022-3227.vid This paper presents the implementation of stability analysis methods in the CHApel Multi-Physics Simulation (CHAMPS) software. A classic method using the extraction of the Jacobian matrix of the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations and a resolution of eigenvalue problems with the PETSC and SLEPC libraries is implemented. A development to compute the stability of spanwise invariant flow with an assumption on the periodicity of the modes in the spanwise direction is included. This paper also proposes a matrix-free implementation, which relies on a Generalized Minimized Residual solver for the linear systems of equations. In all cases, an Arnoldi iteration with the shift-and-invert spectral transformation is used to compute the eigenpairs. The methods are verified for the case of a laminar cylinder and the transonic buffet over an airfoil, and applied to a transonic buffet case on a half wing-body aircraft configuration.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.002 | 0.003 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.028 | 0.010 |
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".