[lost.identity]

I have seen a number of forum posts on this topic but I'm still struggling with my boundary conditions.

I'm running a 1-D spherical calculation (only radial dependence considered). I decided to have velocity boundary conditions at the inlet and outlet. So the BCs I have are:

inlet:
outlet: which is zero gradient BC.

I understand that for subsonic simulations you either have to specify velocity or pressure BCs. I have a staggered grid where the velocities are staggered forward.

My discretised equation for the pressure looks of the form



I used the discretised equation to calculate the pressure values at the boundary. At the inlet since I have therefore, I do not have in the discretised pressure equation and for the outlet I do not have . Is this correct?