High-resolution direct numerical simulations of flow structure and aerodynamic performance of wind turbine airfoil at wide range of Reynolds numbers

Nakhchi, M.E.; Naung, Shine Win; Rahmati, Mohammad

doi:10.1016/j.energy.2021.120261

Cited by 16 publications

(10 citation statements)

References 34 publications

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“…By performing time-integration on the momentum equation and using the above expressions for the advection, Poisson and Helmholtz terms, the momentum equation in n+1 th time-step can be discretised as follows [23]:…”

Section: Physical Modelmentioning

confidence: 99%

“…However, their analysis is based on a stationary blade and the unsteady effects due to blade elasticity are completely ignored. Nakhchi et al [23] performed DNS over the NACA airfoils at a wide range of design parameters to predict the flutter instabilities over the wind turbine blades under realistic flow conditions. It was revealed that increasing the Reynolds number makes the vortex generation stronger and increases the pressure fluctuations on the airfoil surface.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of blade vibrations on aerodynamic performance of axial compressor in gas turbine: Direct numerical simulation

Nakhchi

Naung

Rahmati

2022

Energy

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This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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Section: Physical Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of blade vibrations on aerodynamic performance of axial compressor in gas turbine: Direct numerical simulation

Nakhchi

Naung

Rahmati

2022

Energy

Self Cite

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“…In the field of turbomachinery, many scholars [15][16][17] have used the typical NACA blade in related research. To verify the accuracy of the numerical approach by comparing the calculation result with experimental data, taking into account the existing experimental data of relevant NACA [18,19], the NACA0018 blade was taken as the study target in this paper.…”

Section: Investigation Objectmentioning

confidence: 99%

Aeroacoustic Optimization of the Bionic Leading Edge of a Typical Blade for Performance Improvement

Liu

Yang

et al. 2021

Machines

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New, innovative optimization approaches to improve turbomachine performance and reduce turbomachine noise are significant in engineering. In this paper, based on the bionic concept, a wave structure is used to shape the leading edge of the blade. Using an NACA0018 blade as the basic blade, a united parametric approach controlled by three parameters is proposed to configure the wavy leading edge. Then, a new optimization strategy boosting design efficiency is established to output the optimal design results. Finally, the corresponding performance and flow mechanism are analyzed. Taking into account the existence of the hub wall and the shroud wall from the closed impeller, a near-wall adjustment factor is added, the significance of which is herein demonstrated. An optimal bionic blade is successfully obtained by the optimization strategy, which can reduce the mean drag coefficient by about 6% and the overall sound pressure level by about 3 dB, in relative to the original blade. Mechanism analysis revealed that the wave structure can induce spanwise velocity at the leading edge and cause a further delay in flow separation in the downstream region, synchronously reducing drag and noise.

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“…Recently some high-fidelity approaches to investigate the aerodynamic performance of wind turbine airfoils have attracted attention. Nakhchi et al 10 applied the direct numerical simulation method (DNS) to wind turbine airfoil simulations at higher Reynolds numbers (up to 1.5 × 10 5 ) for the first time, predicting the turbulence flow structure accurately and saving the computational cost significantly. Naung et al 11,12 presented an efficient nonlinear frequency domain solution method to precisely simulate the flow unsteadiness which is periodic in time for wind turbines in arrays and to analyze the aerodynamic mechanism of oscillating airfoils, which reduced the computational load by one to two orders of magnitude.…”

Section: Introductionmentioning

confidence: 99%

Stochastic parameterized modeling for aerodynamic design of wind turbine airfoil

Wang

Chen

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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Aerodynamic optimization of the airfoil is of great significance to the shape design for wind turbine blade. However, it is tough to calculate the aerodynamic forces of airfoil with random shape variations. In response to this challenge, a stochastic parameterized model based on uncertainty quantification method is proposed. And the influence of non-deterministic airfoil geometry caused by designed parameters on the aerodynamic characteristics is evaluated through the combination of sparse grid-based polynomial chaos (SGPC) and computational fluid dynamic (CFD) taking two airfoils at different Reynolds numbers as examples. OpenFOAM is employed as CFD solver and connected with the in-house stochastic parametric analysis code in a non-intrusive way. Finally, the aerodynamic responses of lift, drag, as well as the surface pressure coefficients are obtained, and the sensitivity of the lift and drag coefficients to the stochastic designed parameters are evaluated. It can be concluded that for the same type airfoil, the sensitive parameters after stall behavior are effected to some extent by increasing Reynolds number, that is, the impact of the maximum curvature index on pressure surface is weakened. As for two kinds of airfoils, S809 is sensitive to parameters near the maximum curvature of the airfoil and the trailing edge of the suction surface under attached flow, while convert to those near the leading edge and maximum curvature of suction face once stalled. FFA-W3-241 airfoil has no sensitivity factors in attached flow and features the same sensitive indicators after stall. These results will provide a reference for coarse-to-fine strategy in optimizing the sample library which is generally the first step of airfoil design process.

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High-resolution direct numerical simulations of flow structure and aerodynamic performance of wind turbine airfoil at wide range of Reynolds numbers

Cited by 16 publications

References 34 publications

Influence of blade vibrations on aerodynamic performance of axial compressor in gas turbine: Direct numerical simulation

Influence of blade vibrations on aerodynamic performance of axial compressor in gas turbine: Direct numerical simulation

Aeroacoustic Optimization of the Bionic Leading Edge of a Typical Blade for Performance Improvement

Stochastic parameterized modeling for aerodynamic design of wind turbine airfoil

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