Mach designing

The Mach Number is a dimensionless value useful for analyzing fluid flow dynamics problems where compressibility is a significant factor. The bulk modulus elasticity has the dimension pressure and is commonly used to characterize the fluid compressibility.

The Mach number is used to describe an airplane's speed in terms of the speed of sound. A plane's Mach number is determined by dividing the airplane's speed by the speed of sound. A plane traveling at the speed of sound has a speed of Mach.