CFD Investigation of a Mobula Birostris-Based Bionic Vortex Generator on Mitigating the Influence of Surface Roughness Sensitivity of a Wind Turbine Airfoil

Abstract

In wind turbines, increased blade surface roughness accelerates fluid separation and reduces blade aerodynamic performance. As a flow separation control device, a vortex generator can be used to modulate the fluid flow in the boundary layer and reduce the adverse effect of increased roughness on the aerodynamic performance of the blade. To improve the effect of the vortex generator, a bionic vortex generator based on the anatomy of manta rays is here proposed and commercial CFD software ANSYS CFX is used for numerical simulation. We found that when the equivalent roughness is 0.045 mm, the starting performance of the DU97-W-300 airfoil is consistent with the experimental value observed for installed zigzag tape. Under different roughness conditions, the optimization of the blade aerodynamic performance of the bionic vortex generator is up to 10% higher than that of the triangular vortex generator. The presence of the vortex generator not only increases the maximum lift coefficient of the contaminated blade, but also delays the stall angle, and at the same time increases the suction power of the entire suction surface of the blade. The vortex generator has little effect on the pressure surface.

Keywords

• Bionic
• equivalent sand-grain roughness
• roughness sensitivity
• surface degradation
• vortex generator
• zigzag tape