Linear feedback stabilization of laminar vortex shedding based on a point vortex model
Bibliographic record
Abstract
In this paper we use the Föppl point vortex system as a reduced-order model for stabilization of the steady symmetric solution in an unstable laminar wake. The downstream location of the Föppl vortices is chosen so as to produce the same recirculation length as in the actual flow at a given Reynolds number. When the cylinder rotation is used as flow actuation, the linearized Föppl system is shown to be stabilizable, but not controllable. With centerline velocity measurements as the system output, the linearized Föppl model is also shown to be fully observable. The Linear-Quadratic-Gaussian (LQG) control design is performed based on the linearized Föppl system which has only four degrees of freedom. Computational results show that thus designed LQG compensator stabilizes the stationary solution of the nonlinear Föppl system. When applied to an actual cylinder wake at Re=75, the LQG compensator stabilizes the downstream region of the flow. Possibilities and limitations of flow control strategies based on point vortex systems as reduced-order models are discussed.
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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".