subsonische

Subsonische is the term used in Dutch and German to describe phenomena, speeds, or flows below the speed of sound; in English the corresponding term is subsonic. The speed of sound depends on temperature and medium, and in dry air at sea level it is about 343 meters per second, though this value varies with conditions.

In aerodynamics and fluid dynamics, the subsonische regime generally refers to Mach numbers well below 1.0, commonly up to about Mach 0.8–0.9 depending on context. In this range, pressure disturbances propagate upstream and downstream, allowing relatively gentle compressibility effects. Air behaves almost incompressibly for many practical purposes, and many equations assume constant density as an approximation. As speed increases toward the transonic range near Mach 0.8–1.0, compressibility effects grow and flow features such as shock waves begin to appear.

Applications and design considerations in the subsonische regime emphasize efficiency, stability, and noise control. Most commercial airliners and general aviation aircraft are optimized for subsonic cruise, prioritizing fuel efficiency and predictable handling at speeds below Mach 1. Propeller aerodynamics, intake design, and aeroelastic considerations are typically approached within this regime, where the physics is dominated by gradual pressure changes rather than strong shock phenomena.

Relation to other regimes: subsonische conditions are distinct from transonic, supersonic, and hypersonic regimes, which feature increasingly complex compressibility effects and shock structures. While research continues into higher-speed flight, the subsonische domain remains central to civilian aviation and many engineering applications.