Document Type : Research Paper


1 Mechanical Engineering Dept., University of Technology-Iraq, Alsina’a street, 10066 Baghdad, Iraq.

2 R&D at Pollrich GmbH, Siegen, Germany.


The present study utilizes the commercial software ANSYS-Fluent to explore the influence of the geometry of thick S- S-series airfoil on the near-wake region. Four different S-series airfoils, namely S809, S811, S814, and S818, were investigated at a wide range of angles of attack, which were varied from 0 degrees to 20 degrees with an increment of 2 degrees and at a Reynolds number based on chord length Re = 1x106. Analysis of the resultant data revealed that the aerodynamic performance of the S811 and S818 airfoils superseded that of the S809 and S814 airfoils. To illustrate, at the critical angle of attack, S811 and S818 were observed to possess the maximum lift and minimum drag coefficients. Furthermore, in the range of attack angles between 10 and 16 degrees, these airfoils consistently demonstrated lower drag than the others tested, enhancing overall aerodynamic performance. These findings underscore the significant role played by airfoil geometry in influencing aerodynamic performance and provide insights into optimal design parameters for wind turbine blades, particularly highlighting the advantages of the S811 and S818 airfoil shapes. In addition, the effect of the unsteady structures in the near-wake zone behind the trailing was also evaluated through turbulence kinetic energy contours. The results revealed a decrease in turbulence kinetic energy when the S811 and S818 airfoils were placed in a cross-flow compared to the S809 and S814 airfoils. This indicates that the strength of the vortex shedding of these airfoils is lower than that of the S809 and S8014 airfoils.

Graphical Abstract


  • Ansys-Fluent predicts flow around thick airfoils wall at low/mid angles. High angles: lift, drag, near-wake
  • The airfoil shape significantly shapes the airfoil and wake region flow
  • S818, S811 airfoils performed best in crossflow while S809, S814 showed poor aerodynamics, especially at high angles


Main Subjects

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