In aerodynamic wing theory, the lift force generated by air flowing past an aircraft wing profile is fundamentally linked to fluid circulation. According to the foundational Kutta-Joukowski Theorem in aerospace engineering, the aerodynamic lift force vector per unit wing span () is directly proportional to the cross product of the free-stream airflow velocity vector () and the bound circulation vector ():
where is the ambient air density.
Consider an aircraft flying through cruising altitude where the air density is . The relative wind velocity flowing horizontally past the wing chord is , and the bound circulation around the airfoil profile is oriented along the spanwise direction as .
- Compute the cross product .
- Determine the resulting lift force vector per unit span () in Newtons per meter ().
- State the spatial direction in which the lift force acts.