Geometrical Effect of Tube Array on Prediction of Fluidelastic Instability – Single Phase Air Flow
Bibliographic record
Abstract
Abstract Flow-induced vibrations (FIV) are a major consideration in the design of shell and tube heat exchangers. Among the FIV excitation mechanisms, fluidelastic instability (FEI) is by far the most important mechanism that can significantly compromise the structural integrity of tube arrays. Traditionally, FEI was thought to only occur in the transverse direction. The recent tube failures of replacement steam generators showed that FEI could occur in the streamwise direction and be equally devastating. This has sparked intensive efforts to uncover the nature of this new phenomenon. The current work presents an experimental investigation program which was initiated to systematically uncover fundamental aspects of this phenomenon. Experiments were carried out in an airflow wind tunnel at the University of Guelph in the Fluid-Structure Interaction Laboratory. The aim of this study was to investigate the geometrical effect of tube array types on the FEI in both the transverse and streamwise directions. The stability of a single flexible tube and multiple flexible tubes in tube arrays were tested. Parallel triangle and normal triangle arrays were tested at pitch ratios in the range of 1.25 to 1.7. A compression between the available experimental data and the current result was presented and conclusions were drawn. The results show that the stability threshold is sensitive to the pitch-to-diameter ratio of the array and the number of flexible tubes especially in the streamwise direction.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| 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) | 0.000 | 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 teacher head, 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".