What is drag coefficient?

The drag coefficient is a dimensionless quantity that is used to quantify the resistance of an object as it moves through a fluid, such as air or water. It is defined as the ratio of the drag force experienced by an object to the product of the fluid's density, the object's velocity, and the object's cross-sectional area.

A lower drag coefficient indicates that an object is more streamlined and experiences less resistance as it moves through the fluid. This is often desirable in applications such as cars, airplanes, and boats, where reducing drag can improve efficiency and reduce fuel consumption.

Factors that can affect the drag coefficient of an object include its shape, size, surface roughness, and orientation relative to the direction of flow. Engineers use computational fluid dynamics (CFD) simulations and wind tunnel testing to optimize the design of objects for minimum drag and maximum performance.