Staggered grid outflow boundary condition
 

I am facing a problem in the implementation of the outflow boundary condition on staggered grid. Pressure grid nodes (0 to n) and velocity (0 to n+1).
No pressure nodes on the boundaries to avoid complications of half CV length involvement, from the advection point of view it should not affect and it does not by forcing the reflective boundary condition u[n+1]=0. it works fine:).
But with the implementation of outflow boundary condition p[n]=p[n-1] and u[n+1]=u[n], m not getting the correct results. Implementation has been done far away from the source ensuring a developed velocity profile.
so please help.