Drag Divergence

Drag Divergence is a phenomenon that occurs when an airfoil’s drag increases sharply and requires substantial increases in power (thrust) to produce further increases in speed. This is not to be confused with MACH crit. The drag increase is due to the unstable formation of shock waves that transform a large amount of energy into heat and into pressure pulses that act to consume a major portion of the available propulsive energy. Turbulent air may produce a resultant increase in the coefficient of drag.