If there is a myth needing busting it is that ASIs are calibrated according to the incompressible solution of the Euler equations. ASIs are calibrated to respond to impact pressure (St Venant's 'compressible' solution of the Euler equation).
Covered previously at:
Old Smokey's 2006-01-12 post on dynamic -v- impact pressure here:
http://www.pprune.org/questions/2057...ml#post2318100
Equations are in
NACA Technical Report 837 (Langley, 1946),
NACA UK Mirror report description page