Transonic Low Reynolds number Airfoil Optimization using Discrete Adjoint Method

The increasing interest on flying on different planets from earth, whose atmospheres have mainly low density, has brought the need of analysing the low Reynolds aerodynamics characteristics of airfoils. Moreover, atmospheres as that of Mars, where the decrease of density is not accompanied by an equal decrease on gravity acceleration, makes difficult flying in subsonic regimes for aircraft. Therefore, this paper targets the optimization of an airfoil in transonic low Reynolds number flows. The method of optimization chosen is the adjoint multipoint optimization, first used in steady state simulations, then in time-dependent simulations. In the end, the new airfoils are analysed at three different Reynolds and Mach conditions and their polars are compared with that of the initial airfoil.