Prandtl-Glauert rule

Prandtl-Glauert rule

[′pränt·əl ′gläu̇·ərt ‚rül]
(fluid mechanics)
The rule that the pressure coefficient at any point in the subsonic flow of a fluid about a slender body is equal to the pressure coefficient at that point in the corresponding incompressible fluid flow, divided by √(1 -M 2), where M is the Mach number far from the body.