Drag area

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.^[1] The drag area is usually expressed as a product ${\displaystyle C_{d}A,}$ where ${\displaystyle A}$ is a representative area of the object, and ${\displaystyle C_{d}}$ is the drag coefficient, which represents what shape it has and how streamlined it is.^[1]

The drag coefficient plays a role in Reynold's drag equation,

${\displaystyle F_{d}={\frac {1}{2}}\ \rho \ C_{d}A\ v^{2}.}$

Here, ${\displaystyle F_{d}}$ is the drag force, ${\displaystyle \rho }$ the density of the fluid, and ${\displaystyle v}$ the speed of the object relative to the fluid.

See also

• Drag (physics)
• Automobile drag coefficient#Drag area
• Zero-lift drag coefficient