New guy here. Question on Unconstrained shape design of a transonic inviscid airfoil
 

I was doing a tutorial Unconstrained shape design of a transonic inviscid airfoil at a cte AoA. And I cant figure out how final evuluation was chosed as optimal shape. I understand that it try to decreases the drag to minimal but I want to know it in a bit more detail. Can someone explain how final shape is actually chosen?

The su2 website contains a list of papers published on the topic of adjoint optimization, e.g. this one from Tom Economon:


https://su2code.github.io/documents/AIAA-2018-3111.pdf