Experimental Study of a Bulb Turbine Model During Start-Up and at Speed-No-Load Conditions, Based on the Measurement of Unsteady Pressure
Bibliographic record
Abstract
Abstract Experimental analysis of a bulb turbine during the start-up sequence and in speed-no-load (SNL) operating conditions was performed in a closed-loop circuit. This study focuses on pressure fluctuations across the machine. The turbine was equipped with 26 pressure sensors on one runner blade and 16 in the stationary reference frame. Strain measurements were also performed on two other runner blades. The first section of this analysis focuses on SNL operating conditions using standard Fourier data processing. The results show that three rotating flow phenomena are only present close to the runner. One of them corresponds to the interblade vortex at f/fr=4.00, whereas the two others, which have subsynchronous runner frequencies, are consistent with a possible rotating stall. These phenomena, which exist predominantly on the suction side, have a strong influence on runner blade strain. The second section of the study concentrates on a time-frequency analysis using the Morlet wavelet transform. It reveals that the two subsynchronous flow structures appear at the end of the start-up and exhibit bistable behavior. As well, each of these phenomena acts differently on the blade. These phenomena also interact with the interblade vortex.
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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) | 0.001 | 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 | 0.000 |
| 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".