Coefficient of drag

In fluid dynamics, the drag coefficient (commonly denoted as: ${\displaystyle \scriptstyle C_{\mathrm {d} }\,}$, ${\displaystyle \scriptstyle C_{\mathrm {x} }\,}$ or ${\displaystyle \scriptstyle C_{\mathrm {w} }\,}$) is a dimensionless quantity that is used to quantify the drag or resistance of an object in a fluid environment, such as air or water. It is used in the drag equation in which a lower drag coefficient indicates the object will have less aerodynamic or hydrodynamic drag. The drag coefficient is always associated with a particular surface area.

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