text: The magnitude of stagnation pressure can be derived from Bernoulli equation for incompressible flow and no height changes. For any two points 1 and 2:
  The two points of interest are 1) in the freestream flow at relative speed  where the pressure is called the "static" pressure, (for example well away from an airplane moving at speed ); and 2) at a "stagnation" point where the fluid is at rest with respect to the measuring apparatus (for example at the end of a pitot tube in an airplane). 
  Then 
  or
  where:
  : is the stagnation pressure
  : is the fluid density
  : is the speed of fluid
  : is the static pressure
  So the stagnation pressure is increased over the static pressure, by the amount  which is called the "dynamic" or "ram" pressure because it results from fluid motion.  In our airplane example, the stagnation pressure would be atmospheric pressure plus the dynamic pressure.
  In compressible flow however, the fluid density is higher at the stagnation point than at the static point. Therefore,  can't be used for the dynamic pressure. For many purposes in compressible flow, the stagnation enthalpy or stagnation temperature plays a role similar to the stagnation pressure in incompressible flow.