Entrainment/ free boundary

[AMM]

Hello all,

I am trying to simulate an impinging jet with boundary conditions as shown attached. What is the best way to create an entrainment/ free boundary in basilisk? 

I tried the following Boundary conditions:

u.n[top] = fabs(x) <= R ? dirichlet(Ucl*pow(1.0-((2.0*x)/D),0.138)) : neumann(0.0);

p[top]=fabs(x) <= R ? neumann(0.0): dirichlet(0.0);

u.n[right]=neumann(0.0);

u.t[right]=neumann(0.0);

p[right]=dirichlet(0.0);

and created a wall at the bottom so that I have a rectangular domain.

However, the flow with the above conditions did not sound right. Please find attached the velocity magnitude development of the flow over time