A fully automated optimisation procedure for multi-airfoil configurations based on CFD

Designing and optimising multi-airfoil configurations usually require expensive tests in the wind tunnel and significant computational resources for CFD simulations. This work presents an accurate multi-airfoil optimisation procedure based on CFD with variable-fidelity algorithms coupled with multi-processing capabilities. The overall CFD setup has been developed by analysing several single and multi-element configurations. Geometries can be generated either by using airfoil parameterisations or by providing a list of points. Secondly, the grid generation relies on a fully automated procedure that handles multi-airfoil configurations, providing high quality grids with limited user inputs and consequently avoiding time-consuming manual tunings. About optimisation procedure, several design variables can be selected, such as relative positioning of the airfoils. The user can select different optimisation methods, including Particle Swarm Optimisation (PSO) and Steepest Ascent (or Descent) Optimisation. To determine a proper starting configuration or to cut off the number of configurations to be analysed and quickly converge to an optimal solution, various preliminary low-fidelity methodologies can be selected. The entire methodology shows the feasibility of a CFD optimisation procedure for multi-element airfoils without the need for expensive wind tunnel tests and excessively time-consuming approaches.