Angle of Induced downwash

Angle of Induced downwash

Downwash generated through vortex deflects the airflow from horizontal through an angle called as the angle of induced Downwash. This effect not only occurs behind the wing but also impacts the airflow approaching the wing by deflecting in upward from the horizontal through the same angle (ʠ). The resulting airflow is called effective relative airflow and the angle between effective relative airflow and the horizontal is called Ineffective angle of attack.

The resultant lift force which acts perpendicular to the relative airflow is also deflected rear ward through the same angle (ʠ_i). The angle of attack producing this Lift force is called effective angle of attack (ʠ_e) which is the angle between chord line and effective relative airflow. A portion of lift tends to retard the forward motion of the aircraft is called Induced drag which acts horizontally rearwards.

The amount of lift acting vertically upwards is calculated by the effective angle of attack and it is called Effective Lift. If the effective angle of attack is smaller, lift generated is reduced. the amount of lift generated increases from the wing tips in span wise direction.

To recover the lost lift ,angle of attack must be further increased to maintain the effective angle of attack, which also influences the drag component.

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