Comparison of low, medium and high fidelity numerical methods for unsteady aerodynamics and nonlinear aeroelasticity

Fernandez-Escudero, Claudia; Gagnon, Miguel; Laurendeau, Éric; Prothin, Sebastien; Michon, Guilhem; Ross, Annie

doi:10.1016/j.jfluidstructs.2019.102744

Cited by 9 publications

(2 citation statements)

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“…Studies have found that the flat-vortex-sheet approximation is reasonable when bodies undergo small-to-moderate deflections (Izraelevitz, Zhu & Triantafyllou 2017; Fernandez-Escudero et al. 2019). The approximation worsens at larger membrane deflections, where the wake deflection would become similarly large and other inviscid approximations (e.g.…”

Section: Methodsmentioning

confidence: 99%

Membrane flutter in three-dimensional inviscid flow

Mavroyiakoumou

Alben

2022

J. Fluid Mech.

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We develop a model and numerical method to study the large-amplitude flutter of rectangular membranes (of zero bending rigidity) that shed a trailing vortex-sheet wake in a three-dimensional (3-D) inviscid fluid flow. We apply small initial perturbations and track their decay or growth to large-amplitude steady-state motions. For 12 combinations of boundary conditions at the membrane edges we compute the stability thresholds and the subsequent large-amplitude dynamics across the three-parameter space of membrane mass density, pretension and stretching rigidity. With free side edges we find good agreement with previous 2-D results that used different discretization methods. We find that the 3-D dynamics in the 12 cases naturally forms four groups based on the conditions at the leading and trailing edges. The deflection amplitudes and oscillation frequencies have scalings similar to those in the 2-D case. The conditions at the side edges, although generally less important, may have small or large qualitative effects on the membrane dynamics – e.g. steady vs unsteady, periodic vs chaotic or the variety of spanwise curvature distributions – depending on the group and the physical parameter values.

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Section: Methodsmentioning

confidence: 99%

Membrane flutter in three-dimensional inviscid flow

Mavroyiakoumou

Alben

2022

J. Fluid Mech.

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“…Theodorson unsteady aerodynamics is a method of calculating aerodynamic loads using two-dimensional oscillating airfoils. Claudia 13 compared the unsteady vortex lattice, Euler method, and Reynolds averaged Naiver-Stokes method using Theodorsen theory to study the critical flutter velocity and limit cycle oscillation of two-dimensional airfoils under nonlinear conditions. It was pointed out that low fidelity methods can achieve the same phenomenon and reduce calculation time.…”

Section: Introductionmentioning

confidence: 99%

Study on coupled mode flutter parameters of large wind turbine blades

Zhuang,

Yuan

2024

Sci Rep

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As the size of wind turbine blades increases, the flexibility of the blades increases. In actual operation, airflow flow can cause aerodynamic elastic instability of the blade structure. Long blades may experience coupled mode flutter due to the bending torsion coupling effect, leading to blade failure. Based on Euler Bernoulli beam theory combined with Theodorsen non directional aerodynamic loads, a blade flutter characteristic equation is established through finite element method. Taking NREL 5 MW wind turbine blades as an example, analyze the influence of parameter changes in different regions of the blades on flutter characteristics. Research has found that paramter changes in the tip region of blade have the greatest impact on flutter characteristics. The vibration frequency shows an overall upward trend with the increase of waving stiffness and torsional stiffness. The flutter velocity of the three regions tends to stabilize as the bending stiffness decreases. The blade flutter speed increases with the increase of torsional stiffness. The radius of gyration is inversely proportional to the flutter frequency and flutter velocity. The impact of centroid offset on blade structure flutter frequency is minimal, but the centroid offset in the tip region has a greater impact on flutter velocity. Increasing the torsional frequency can prevent coupled mode flutter and provide a theoretical basis for blade flutter prevention design.

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