Therefore, there is a need to develop an intuitive understanding of the force generation mechanism that does not rely on these assumptions.

In fact, when massive flow separation occurs, the underlying assumptions of thin airfoil theory and lifting line theory are violated and the concept of bound circulation cannot be applied. However, the common understanding of the lift generation mechanism holds only for attached flow conditions. Filename: Viola_etal_OE_2021_The_force_generation_mechanism_of_lifting_surfaces.pdfįins, wings, blades and sails can generate lift and drag in both attached and separated flow conditions.