Wave Drag (Paperback)

High Quality Content by WIKIPEDIA articles Wave drag is an aerodynamics term that refers to a sudden and very powerful form of drag that appears on aircraft and blade tips moving at high-subsonic and supersonic speeds. Wave drag is caused by the formation of shock waves around the aircraft. Shock waves radiate away a considerable amount of energy, energy that is experienced by the aircraft as drag. Although shock waves are typically associated with supersonic flow, they can form at much lower speeds at areas on the aircraft where local airflow accelerates to supersonic speeds. The effect is typically seen at transonic speeds above about Mach 0.8, but it is possible to notice the problem at any speed over that of the critical Mach of that aircraft's wing. The magnitude of the rise in drag is impressive, typically peaking at about four times the normal subsonic drag. It is so powerful that it was thought for some time that engines would not be able to provide enough power to easily overcome the effect, which led to the concept of a "sound barrier."