Circulation () around an airfoil refers to the net flow of fluid rotation per unit time that occurs as air flows around the airfoil in an aerodynamic field. It is a fundamental concept in fluid dynamics and aerodynamics, particularly in the context of lift generation and the behavior of wings or airfoils.
- is the circulation, which is a measure of the flow’s rotational strength around the airfoil. It quantifies the net amount of fluid rotation per unit time.
- is the chord length of the airfoil.
- is the freestream velocity of the airflow.
- is the area enclosed by the airfoil itself.
- is the area enclosed by a line connecting the leading and trailing edges of the airfoil, also known as the Kutta-Joukowski area.