Drag coefficient

In fluid dynamics, the drag coefficient (commonly denoted as: C d {displaystyle scriptstyle C_{mathrm {d} },} , C x {displaystyle scriptstyle C_{mathrm {x} },} or C w {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. In fluid dynamics, the drag coefficient (commonly denoted as: C d {displaystyle scriptstyle C_{mathrm {d} },} , C x {displaystyle scriptstyle C_{mathrm {x} },} or C w {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. The drag coefficient of any object comprises the effects of the two basic contributors to fluid dynamic drag: skin friction and form drag. The drag coefficient of a lifting airfoil or hydrofoil also includes the effects of lift-induced drag. The drag coefficient of a complete structure such as an aircraft also includes the effects of interference drag. The drag coefficient c d {displaystyle c_{mathrm {d} },} is defined as