Numerical simulation of the hydrodynamic damping of a vibrating hydrofoil

Tengs, Erik Os; Bergan, Carl Werdelin; Jakobsen, K.; Storli, Pål-Tore Selbo

doi:10.1088/1755-1315/240/6/062002

Cited by 8 publications

(4 citation statements)

References 7 publications

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“…A constant load is used in all the simulations. This load was obtained from a CFD simulation on the same geometry, where the blade was vibrating at its natural frequency [27]. The fluid load (pressure) is imported to the blade in the harmonic analysis.…”

Section: Numerical Setupmentioning

confidence: 99%

Model Order Reduction Technique Applied on Harmonic Analysis of a Submerged Vibrating Blade

Tengs

Charrassier

Holst

et al. 2019

International Journal of Applied Mechanics and Engineering

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As part of an ongoing study into hydropower runner failure, a submerged, vibrating blade is investigated both experimentally and numerically. The numerical simulations performed are fully coupled acoustic-structural simulations in ANSYS Mechanical. In order to speed up the simulations, a model order reduction technique based on Krylov subspaces is implemented. This paper presents a comparison between the full ANSYS harmonic response and the reduced order model, and shows excellent agreement. The speedup factor obtained by using the reduced order model is shown to be between one and two orders of magnitude. The number of dimensions in the reduced subspace needed for accurate results is investigated, and confirms what is found in other studies on similar model order reduction applications. In addition, experimental results are available for validation, and show good match when not too far from the resonance peak.

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Section: Numerical Setupmentioning

confidence: 99%

Model Order Reduction Technique Applied on Harmonic Analysis of a Submerged Vibrating Blade

Tengs

Charrassier

Holst

et al. 2019

International Journal of Applied Mechanics and Engineering

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“…However, it decreases the damping after lock in [5]. Two different behaviors were observed for the damping of a vibrating hydrofoil function of the free-stream velocity [6][7][8][9]. The damping was constant at low velocity and before lock-in, whereas it increased linearly with the rise of the free-stream velocity after lock-in.…”

Section: Introductionmentioning

confidence: 99%

“…Bergan et al [6] attributed this behaviour to the change of phase difference between the vortex shedding and the imposed oscillation velocity. However, they later observed that the phase of the vortex shedding had an adverse effect on the damping with the increase of the velocity [7]. It was claimed that the change of the phase shift between displacement and force is the source of the altered behaviour.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of hydrodynamic damping of a pitching hydrofoil at different flow regimes

Bahrami,

Raisee,

Cervantes

et al. 2024

J. Phys.: Conf. Ser.

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Due to the development of intermittent renewable energy resources, hydropower plants are mostly operated under off-design conditions. This may lead to natural frequency excitation shortening the turbine life-span. To accurately estimate the fatigue life, it is necessary to evaluate the hydrodynamic damping parameters. In the present study, different flow regimes and their relationship with hydrodynamic damping are analyzed numerically using the γ - Reθt transition SST ĸ - ω turbulence model. The test case is a NACA0009 hydrofoil pitching around its center of mass. A good agreement between the present and previous numerical results is obtained. Consistent with the literature, hydrodynamic damping coefficient demonstrate consistently two different regions. The phase shift between the displacement and moment increases with the rise of the pitching frequency. After reaching a peak value at a reduced frequency of around κ = 5, the phase shift starts to decrease, and eventually approaches zero again. The damping behavior demonstrates an opposite trend. First, it reduces in spite of the phase shift increase, and after the inflection point, where the flow field changes from the drag mode to the thrust mode, it rises due to the torque development. The maximum of the damping occurs at the low frequencies.

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“…However, for submerged structures, the mode shape change due to the water flowing usually is not significant, together with considering the much less calculation cost compared with the two-way FSI method, the one-way FSI method is also used by many researchers, and good results were obtained compared with experimental results. Tengs et al use the one-way fluidstructure method based on the k − ω SST turbulence model to investigate the added damping of a hydrofoil in flowing water, and little errors were found between the numerical and experimental results [27]. Gauthier et al developed an improved one-way fluid-structure method with the consideration of the added stiffness and added mass change due to the water flowing and applied this method to investigate the added damping of a hydrofoil and a Kaplan turbine runner [28].…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of the Trailing Edge Shape on the Added Damping of a Kaplan Turbine Runner

Zhang

Mbango-Ngoma

et al. 2021

Mathematical Problems in Engineering

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Hydraulic turbine runners experience high excitation forces in their daily operations, and these excitations may cause resonances to runners, which may induce high vibrations and shorten the runner's lifetimes. Increasing the added damping of runners in water can be helpful to reduce the vibration level during resonances. Some studies have shown that the modification of the trailing edge shape can be helpful to increase added damping of hydrofoils in water. However, the influence of blade trailing edge shape on the added damping of hydraulic turbine runners has been studied in a limited way before. Due to the difficulties to study this problem experimentally, the influence of blade trailing edge shape on a Kaplan turbine runner has been studied numerically in this paper and the one-way FSI method was implemented. The performances of three different turbulence models, including the k − ϵ , k − ω SST , and transition SST models, in the added damping simulation of the NACA 0009 hydrofoil were evaluated by comparing with the available results of the two-way FSI simulation in the references. Results show that, unlike the significantly different performances in the two-way FSI method, the performances of all the turbulence models are very close in the one-way FSI method. Then, the k − ϵ turbulence model was applied to the added damping simulation of a Kaplan turbine runner, and results show that the modification of the blade trailing edge shape can be helpful to increase the added damping to some extent.

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Numerical simulation of the hydrodynamic damping of a vibrating hydrofoil

Cited by 8 publications

References 7 publications

Model Order Reduction Technique Applied on Harmonic Analysis of a Submerged Vibrating Blade

Model Order Reduction Technique Applied on Harmonic Analysis of a Submerged Vibrating Blade

Numerical investigation of hydrodynamic damping of a pitching hydrofoil at different flow regimes

Numerical Investigation of the Trailing Edge Shape on the Added Damping of a Kaplan Turbine Runner

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