Staggered Grooves for the Suppression of Vortex-Induced Vibration in Flexible Cylinders
Bibliographic record
Abstract
Abstract Vortex-Induced Vibration (VIV) remains a challenge to the offshore structures such as deepwater riser and subsea pipelines, which require a robust and cost-effective control to circumvent the impact of the dynamic loads and the fatigue damage. While the state-of-the-art helical strakes are effective in the suppression of VIV amplitudes, they cause a higher drag force and bending moment on the submerged structure. In this work, we numerically investigate the recently proposed staggered groove concept to reduce both the VIV amplitudes and the drag force. The staggered groove is constructed by aligning the square grooves alternatively along the spanwise (axial) direction of the cylinder. The performance of the staggered groove concept is examined in three dimensions for two VIV configurations at subcritical Reynolds number (Re) namely: (i) two-degree-of-freedom elastically mounted rigid cylinder (Re = 3000–10000), and (ii) pinned-pinned flexible cylinder in a uniform current flow at Re = 4800. Their characteristic responses and the vortex dynamics are compared to their plain cylinder counterparts. For the two VIV configurations, our results show a remarkable reduction of both the peak vibration amplitude and the drag force up to 40% and 20%, respectively. Further analysis has shown that such reduction is related to the diminishing of the spanwise correlation of hydrodynamic forces due to the alternating alignment of the grooves. Such effect on the spanwise correlation leads to the broadening of the frequency spectra of the forces, thereby reduces the average power transferred to the cylinder and leads to the VIV suppression.
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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".