Low-Order Models of the Fluctuating Wall Pressure in an Incompressible Turbulent Impinging Jet
Bibliographic record
Abstract
The ∞uctuating wall pressure fleld measured simultaneously at 137 points in an impinging jet with ReD = 23;000 and a nozzle-to-plate spacing of two diameters. A previous time averaged azimuthal decomposition 1 indicated that the ∞uctuating pressure fleld could be accurately described using few azimuthal modes, indicating this ∞ow is an excellent candidate for a Low-Order Dynamical Systems (LODS) model. The present model was developed using a method similar as Ricaud, 2 whereby a general cubic order system of equations is flt to the experimentally determined Fourier coe‐cients. A LODS model developed using only azimuthal modes 0, 1 and 2 was able to reasonably accurately capture the behaviour of the ∞uctuating pressure fleld at r=D = 1:5. Downstream at r=D = 2:0, where the pressure fleld is more three-dimensional, the addition of azimuthal mode 3 is required to produce a stable system of equations, that again, reasonably captures the dynamics of the ∞uctuating pressure fleld. The success of this technique here, suggests that it may prove useful in high speed ∞ow control applications where some degree of predictive ability is required.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".