Dear Kratos team,

I was checking today the *fractional_step_discontinuous.cpp* file. However I do not understand very well from a theoretical point of view how it is the embedded velocity imposed into the element and the penalty coefficient used for that. I can understand the weak imposition in the mass conservation equation but not very well how the velocity is imposed in the momentum equation. Is there some theory or article which explains this procedure?

Thank you for your help!

Carlos