Suppressing tip vortex cavitation through passive deformation of a hydrofoil. I. Bending
Bibliographic record
Abstract
Tip vortex cavitation (TVC) remains a persistent issue in marine propulsion and lifting surfaces, contributing to the underwater radiated noise of marine vessels. We investigate a novel passive strategy for TVC mitigation through localized chord-normal bending of an elliptical NACA (National Advisory Committee for Aeronautics) 66(2)-415 hydrofoil. The hydrofoil is geometrically modified using modal deflection shapes characterized by spanwise bending length and deflection angle on the suction or pressure side. High-fidelity large eddy simulations of cavitating multiphase flow in various bending configurations are performed using our recently developed variational cavitation flow solver. These bending configurations involve full-, half-, and quarter-span bending by bending angles within the range of −20° to 30°. The effect of these parameters on the core pressure of the tip vortex, the cavitation volume, and the hydrodynamic performance is assessed. The results demonstrate that chord-normal bending, both toward the suction and pressure sides, can weaken the tip vortex flow and suppress TVC with pressure-side bending leading to superior TVC mitigation. Examining the hydrodynamic performance of the hydrofoil in various bending configurations reveals that pressure-side bending leads to reduced drag and improved lift, resulting in an improved lift-to-drag ratio compared to the baseline hydrofoil. However, a minor reduction in lift and an increase in drag are observed in the case of suction-side bending. Quantitative comparisons using a newly introduced integrated performance index (IPI) reveal optimal tradeoffs between cavitation suppression and lift-to-drag performance. Among the various bending configurations studied in this work, the highest IPI is observed in the HS−N20 (half-span bending by −20°) case, in which the tip vortex cavity volume is decreased by 99.5% at σ=1.4 compared to the plain hydrofoil, and an improvement by 9.9% is achieved in the lift-to-drag ratio. Through a detailed analysis of the tip vortex circulation, wake behavior, and boundary layer flow, we show that pressure-side bending weakens the rolled-up circulation via reduced spanwise advection of wake vorticity. In contrast, suction-side bending delays vortex formation by limiting the initial spanwise boundary layer flux near the tip. These findings establish chord-normal bending as a promising passive design paradigm for cavitation control in marine propulsors and lifting surfaces.
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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 | 0.001 |
| 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".