Experimental analysis of fluid elastic vibrations in rotated square finned tube arrays subjected to water cross flow
Bibliographic record
Abstract
The majority of the failures of shell and tube heat exchanger tubes are reported due to the flow-induced vibration caused by shell side cross flow. Fluid elastic instability, vortex shedding, and turbulent buffeting are the excitation mechanisms responsible for the failure of the tubes. The failure occurs due to tube-to-tube impacts leading to impaction marks on the tube surface and, subsequently, leading to the failure due to fretting wear and fatigue. The present research work deals with the determination of critical velocity at instability for rotated square finned tube arrays subjected to water cross flow. In all, total six tube arrays are tested with two different pitch ratios, each with a plain tube array, a coarse finned tube array, and a fine finned tube array. Pitch ratios considered in the study are 2.1 and 2.6, while fin densities considered are coarse (4 fpi = 6.35 mm) and fine (10 fpi = 2.54 mm). The effect of array pattern, pitch ratio, and fin density on the onset of instability is studied by conducting experiments in the water cross flow. The effect of tube array pattern is studied by comparing the results of the present study with authors' published results for parallel triangular finned tube arrays in the water cross flow. The study led to the conclusion that the instability threshold is delayed for rotated square tube arrays compared to parallel triangular tube arrays. It is also observed that instability thresholds for coarse and fine finned tubes are delayed compared to plain tubes and is found to be more for finned tubes with higher fin densities.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.004 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 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".