Free Stream Flow in Aircraft Aerodynamics

Free Stream Flow in Aircraft Aerodynamics

Free stream flow refers to the undisturbed airflow relative to the aircraft—the air the aircraft encounters as it moves through the atmosphere. It is characterized by:

• Velocity: Determined by aircraft speed and flight path direction.
• Density: Determined by altitude.
• Temperature: Determined by ambient temperature and aircraft speed.

Importance in Design

Free stream conditions are the starting point for calculating aerodynamic forces and moments, which determine performance, stability, and control. Factors like other aircraft, buildings, or terrain can disturb the free stream, causing turbulence.

Analysis Methods

Computational Fluid Dynamics (CFD) simulations and wind tunnel testing are used to model free stream flow accurately.