3D rotational augmented flow effects on the multidisciplinary optimization of flatback airfoils

This paper investigates the impact of 3D rotational augmented flow at the root section of wind turbine rotor blades on the multidisciplinary optimization of thick flatback airfoils. Six different flatback airfoils with varying relative thicknesses ranging from 35 % to 50 %, along with various trailing edge gaps, were studied. As the design of airfoil sections is a multidisciplinary field that involves several aerodynamic and structural parameters, the Simulated Annealing (SA) algorithm, which is classified as a stochastic algorithm, was utilized to design the optimized shape of the flatback airfoil sections. The optimization process involved quasi-3D Navier-Stokes CFD calculations, which were performed using the commercial FLUENT code. The design Reynolds number was 6.0 × 106, and the optimized airfoil sections had relative thicknesses of 35 %, 40 %, 45 %, and 50 %, with a trailing edge gap ranging from 12.5 % to 20 %. The results were compared with previously optimized airfoils using a 2D flow solver. The optimization results indicate that the 3D rotational effects play a crucial role in the flow domain near the root area of the blade and should be considered in the design process.