Nahüberschallflug

Nahüberschallflug refers to flight at speeds approaching the speed of sound. This range is typically considered to be between Mach 0.8 and Mach 1.0. During nahüberschallflug, the airflow over the aircraft's surfaces can experience both subsonic and supersonic velocities simultaneously, leading to complex aerodynamic phenomena.

As an aircraft accelerates towards the speed of sound, the air immediately surrounding its surfaces must accelerate as well. At certain points, particularly over curved surfaces like wings, the local airflow velocity can exceed the freestream velocity. When this local velocity reaches Mach 1, a shock wave forms. These shock waves create a significant increase in drag and can also cause a loss of lift, a phenomenon known as compressibility drag or wave drag.

The development of swept wings in the mid-20th century was a direct response to the challenges posed by nahüberschallflug. Sweeping the wings backward effectively reduces the component of airflow velocity perpendicular to the leading edge, delaying the formation of shock waves and mitigating their adverse effects. Understanding and managing these effects are crucial for the design and operation of aircraft that fly in this speed regime, which includes many modern commercial airliners and military jets. The transition through Mach 1, known as the transonic region, is a critical phase of flight that requires careful engineering.