Experimental Study of Fluidelastic Instability in a Parallel Triangular Tube Array
Bibliographic record
Abstract
Fluidelastic instability is a short term failure mode that occurs in tube bundles subjected to cross flow. It is believed that instability occurs due to two possible mechanisms; one is related to fluid coupling of neighboring tubes, the so called “stiffness mechanism”, and the other is related to a “negative fluid damping mechanism” i.e., fluidelastic forces in phase with tube velocity. The usage of a single flexible tube in a rigid array will eliminate the stiffness mechanism effect and leave only the damping mechanism, which makes the problem less complex. This paper presents a fundamental study of fluidelastic instability in a parallel triangular tube array subjected to air cross flow. It is found that a single flexible tube located in the third row of a rigid parallel triangular array does become fluidelastically unstable at essentially the same velocity as for a fully flexible array. However, when the single flexible tube is located in the first, second, fourth, or fifth rows, no instability behavior is detected. It is concluded from this work that, the tube location inside the array affects significantly its fluidelastic instability behavior when tested as a single flexible tube in a rigid array. It follows that a single flexible tube can be used for fundamental study of the phenomenon but not generally to generate stability maps for practical use.
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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 | 0.000 |
| 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) | 0.000 | 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".