Effect of Pitch Spacing on Fluidelastic Forces in a Rotated Triangular Array
Bibliographic record
Abstract
Abstract Time-averaged quasi-static forces are significant in the study of the fluidelastic instability of tube arrays. Furthermore, measuring the fluid force phase from the unsteady force measurements could be used to directly investigate the dynamic behaviour of an array and predict the array instability onset. Force measurements were previously performed for a rotated triangular array with spacing ratio P/D = 1.5. In this paper, a more compact rotated triangular array is studied following the same measurement approach. This rotated triangular array has a pitch ratio P/D = 1.33. Determining the relationship between the fluid force coefficients used in the quasi-steady model, and fluid force phase used to predict the fluid damping, is one of the main objectives of this work. This is in order to relate the fluid forces to the array pitch spacing. This should be a step toward generalizing the quasi-steady model for the rotated triangular array for various pitch ratios. In this paper, the quasi-static fluid forces are measured in single phase (water) and two-phase (air-water) cross flow in the streamwise direction. The quasi-steady model is then solved, using the forces, to predict the fluidelastic instability onset of the array. Model results are also directly compared with vibration experimental results.
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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) | 0.000 | 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".