Hello! I'm developping a simple code for incompressible fluid. I have one problem. How could I get initial condition that satisfies continuity equation, boundary conditions and compatibility condition? I have not found anything about that anywhere. Or can I use Ui = 0 everywhere when I have nonzero Dirichlet condition on U1 at inlet?

Why don't you use the free stream condition as the initial condition i.e ui=U_inf, vi=0,wi=0 U_inf is the velocity at the inlet also.

Thanks! I was not sure if they are correct if have noslip BC in domain also. I am beginner and in my books (Wesseling, Ferziger - Peric ...) was not much about that.

Vladimir,

Solution convergence can often be a little easier if you 'pre-fill' the fluid domain with a prescribed initial velocity. It also leaves less work for the solver to perform.

diaw...