What causes Drag and what are the main different types of Drag?
Solution: In aerodynamics,drag is defined as the force that opposes forward motion through the atmosphere and is parallel to the direction of the free-stream velocity of the airflow. Drag must be overcome by thrust in order to achieve forward motion. Drag is generated by nine conditions associated withthe motion of air particles over the aircraft. There are several types of drag: form, pressure, skin friction, parasite, induced, and wave.
Main different types of Drag:
Induced drag - drag created by the vortices at the tip of anaircraft's wing; Parasite drag - consists primarily of the skin friction, roughness,and pressure drag of the major components Form drag - caused by the air that is flowing over the aircraft orairfoil (Form drag and pressure drag are virtually the same type of drag) Skin friction - aerodynamic force during low-speed subsonic flight isthe shear force caused by viscous airflow over the surfaces of the vehicle Interference drag- Surfaces at angles to each other create turbulence inthe region of the joint. This occurs most frequently at the intersection of the fuselage and wing.