CFD simulation of Smooth and Rough NACA 0012 Airfoils at low Reynolds number
Date
2018-12-11
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Abstract
The objective of this study is to investigate the accuracy of turbulence model prediction in the computational fluid dynamics (CFD) of airfoil aerodynamic performance with and without roughness. It is very important to study the roughness effect on airfoil aerodynamic characteristics for wind turbine blades and aviation. Since roughness alters the lift and drag coefficients, it affects the aerodynamics performance directly. NACA0012 airfoil is used in the CFD simulation. Low Reynolds number of 1.5105 is used to allow comparison to experimental results, and high Reynolds number of 1.5106 is used to check the aerodynamic performance at conditions more suitable to large wind turbines, but for which there is no experimental data. The range of angle of attack (degrees) is from 0˚ - 10˚ as this covers the range that gives maximum power extraction. The roughness is selected from a previous experiment which is a sand grain roughness grit-36 with a 500μm thickness. The equivalent sand roughness height is used in turbulence models for rough surface simulation. This parameter represents the whole effect of the roughness. The simulation results of lift, drag, pressure and skin friction coefficients as well as the lift to drag ratio between smooth and rough surfaces are compared with the available experimental results. Three turbulence models: low Reynolds SST k-ω, transition-SST and SA models were used for the prediction. The results show the surface roughness can decrease the lift coefficient, lift to drag ratio and increase the skin friction and drag coefficients. At the low Reynolds number (1.5105), the prediction of low Reynolds SST k-ω, transition-SST on the smooth surface show a good agreement with the experimental data than SA model. However, only the low Reynolds SST k-ω model has a good consistency with the experimental results on the rough surface. At high Reynolds number (1.5106), the results of transition-SST on drag coefficients are more closed to experimental data than low Reynolds SST k-ω and SA model. Three models have similar results with experimental data on lift coefficients.
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CFD,Airfoil, Aerodynamics
Citation
Li, Y. (2018). CFD simulation of Smooth and Rough NACA 0012 Airfoils at low Reynolds number (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.