Question

Back pressure is equal to downstream of normal shock stagnation pressure

Answer 1

sorry I have not you answer your question

Answer 2

In fluid dynamics, stagnation pressure (or pitot pressure) is the static pressure at a stagnation point in a fluid flow. At a stagnation point the fluid velocity is zero. In an incompressible flow, stagnation pressure is equal to the sum of the free-stream static pressure and the free-stream dynamic pressure.