In mechanics and aerodynamics, the drag area of an object represents the effective size of the object as it is "seen" by the fluid flow around it. The drag area is usually expressed as a product formula_1 where formula_2 is a representative area of the object, and formula_3 is the drag coefficient, which represents what shape it has and how streamlined it is.
The drag coefficient plays a role in Reynold's drag equation,
formula_4
Here, formula_5 is the drag force, formula_6 the density of the fluid, and formula_7 the speed of the object relative to the fluid.