Implimentation of zero-order extrapolation boundary condition
 

I am simulating a hypersonic flow. The flow is hypersonic at both inlet and outlet. I wish to implement zero-order extrapolation boundary condition at outlet. How can it be done in ANSYS Fluent?

The Pressure Outlet can be one possible choice. The Fluent Manual mentions that - "The value of the specified static pressure is used only while the flow is subsonic. Should the flow become locally supersonic, the specified pressure will no longer be used; pressure will be extrapolated from the flow in the interior. All other flow quantities are extrapolated from the interior."

But, there might be a case where the flow is subsonic in a part of the Pressure-Outlet boundary (e.g., near the wall) and supersonic in other part of the same boundary. In that case, pressure boundary will be applied where the flow is subsonic and zero-order extrapolation boundary condition will be used where the flow is supersonic.

However, I wish to extrapolate all the quantities from the interior irrespective of the flow being subsonic or supersonic. How can this be achieved in ANSYS Fluent?