Critical Mach number Critical Mach number In aerodynamics, the critical Mach number (Mcr or M* ) of an aircraft is the lowest Mach number at which the airflow over some point of the aircraft reaches the speed of sound, but does not exceed it. At the lower critical Mach number, airflow around the entire aircraft is subsonic. At the upper critical Mach number, airflow around the entire aircraft is supersonic. For an aircraft in flight, the speed of the airflow around the aircraft differs considerably in places from the airspeed of the aircraft; this is due to the airflow having to speed up
Mach Song to 100,00 copies, distributed through their vast community networks within and without their areas of physical presence. In the aftermath of Hurricane Katrina (2005), Mach Song monthly printed 50,000 additional copies for six months for distribution to hurricane victims. They similarly increased the circulation of Mach Song monthly after Hurricane Ike (2008). Mach Song Mach Song (, literally "Life Stream") is a national monthly bilingual Vietnamese–English newspaper published in Houston, Texas. The paper has a readership of approximately 75,000 in 15 cities across the United States and is published by "Boat People SOS"—a national Vietnamese American 501(c)(3) nonprofit organization. Working