Home › Forums › density functional theory › functions and functionals › Functional example This topic has 0 replies, 1 voice, and was last updated 2 years, 1 month ago by secanell. Viewing 1 post (of 1 total) Author Posts October 26, 2022 at 10:36 am #7439 secanellParticipant The calculation of the friction drag over an airplane wing is a functional. The force is obtained by integrating the shear force over the surface of the wing. Author Posts Viewing 1 post (of 1 total) You must be logged in to reply to this topic. Log In Username: Password: Keep me signed in Log In