Governing equations for mass and momentum conservations for subsonic flow along with the equations for turbulence and porous flow are solved for the honeycomb using commercial CFD . RANS type RNG k-? model is used for the turbulence modeling.
22.
In the case of aircraft, the cloud is caused by stern shock wave associated with a return to subsonic flow behind the aircraft . Since the local Mach number is not uniform over the aircraft, parts of the aircraft may be supersonic while others remain subsonic a flight regime called transonic flight.
23.
At fully supersonic speed, the shock wave starts to take its cone shape and flow is either completely supersonic, or ( in case of a blunt object ), only a very small subsonic flow area remains between the object's nose and the shock wave it creates ahead of itself . ( In the case of a sharp object, there is no air between the nose and the shock wave : the shock wave starts from the nose .)
