Inlet velocity and outlet pressure BC in presence of total pressure and flow rate
 

I am simulating subsonic compressible flow through a duct. Before running the rhoSimpleFoam solver, I am going to use simpleFoam solver for initialization values.

At the duct inlet I am using totalPressure and at outlet I am using flowRateOutletVelocity.

totalPressure will be defined in 0/p file and flowRateOutletVelocity in 0/U file at inlet and outlet patches respectively.

In this case, would it be correct to set zeroGradient boundary condition for velocity at inlet and pressure at outlet ?

My understanding says that the velocity at inlet and pressure at outlet will be calculated based on the boundary conditions. In such a scenario, zeroGradient seems appropriate to me.