2D Numerical Simulation Study of Airfoil Performance
Abstract. The aerodynamic characteristics of DTU-LN221 airfoil is studied. ANSYS Fluent is used to simulate the airfoil performance with seven different turbulence models. The simulation results for the airfoil with different turbulence models are compared with the wind tunnel experimental data performed under the same operating conditions. It is found that there is a good agreement between the computational fluid dynamics (CFD) predicted aerodynamic force coefficients with wind tunnel experimental data especially with angle of attack between −5° to 10°. RSM is chosen to investigate the flow field structure and the surface pressure coefficients under different angle of attack between −5° to 10°. Also the effect of changing air temperature, velocity and turbulence intensity on lift and drag coefficients/forces are examined. The results show that it is recommended to operate the wind turbines airfoil at low air temperature and high velocity to enhance the performance of the wind turbines.
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3. Results and Discussions (Which has no content now)
3.1 Model validation
Right now this section doesn’t contain any material as result or discussion. Most of the text here can be in section 2.3 (Numerical setup) while talking about numerical simulations’ initial and boundary conditions and solution algorithm. I think it’s a good idea to merge 3.1 and what you have as 3.2 under this subsection. Basically, in this subsection, you are observing Cl and Cd of 7 turbulence models in order to find the best turbulence model in comparison with experimental results.
3.2 Effect of Angle of Attack (AOA)
From this subsection, only the results from the RSM turbulence model are presented. In this subsection which I suggest containing the material from both 3.3 and 3.4 of the current draft, you can present all the results which represent the effect of AOA.
3.3 Effect of air temperature
3.4 Effect of air speed
3.5 Effect of turbulence intensity
The aerodynamic characteristics of an airfoil are usually represented by Cl, Cd, and their ratio (AKA L/D), and not lift and drag forces which are directly affected by the air density.
According to the definition of lift and drag force, both of them decrease at the same rate when the temperature increases. As they both decrease at the same rate, they can cancel out each other in L/D and it may have no information about the effect of temperature on the aerodynamic performance of the airfoil. As we see no difference between Cl and Cd profiles in different temperatures. The goal of this section is in the first sentence as "investigating the effect of changing air temperature on the airfoil characteristics"; the difference between lift and drag force in different temperatures cannot explain this.
Section 2.2 is devoted to describing 7 different RANS models; thus, it is more impressive to have 7 subsections, each one dedicated to one of the turbulence models. This is much easier to remember and less confusing for the readers. I suggest moving the content of 2.2.2 to 2.2 . Starting 2.2 with the sentence “In CFD, RANS is …”