Equivalent Theodorsen Function for Fluidelastic Excitation in a Normal Triangular Array
Bibliographic record
Abstract
Abstract Fluidelastic instability (FEI) remains an important concern to designers of heat exchangers subjected to high flow velocities of gases, liquids or a combination of the two phases. In the present work, experimental tests are conducted to measure the quasi-steady fluid forces acting on a normal triangular tube array of P/D = 1.5 subjected to single-phase cross-flow. The quasi-steady forces together with previously measured unsteady fluid forces are used to estimate the time delay between the central tube motion and fluid forces on itself. The time delay effect for the quasi-steady fluidelastic instability model is derived in the frequency domain in the form of an equivalent Theodorsen function. The results are compared with the Theodorsen function previously obtained for the rotated triangular array. Using the time delay formulation, a stability analysis is carried out to predict the critical velocity for fluidelastic instability in a normal triangular array subjected to single-phase flow.
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".