Drag Coefficient

The drag coefficient (often denoted as ) is a dimensionless parameter used in fluid dynamics to quantify the drag or resistance experienced by an object moving through a fluid. It represents the ratio of the drag force acting on the object to the dynamic pressure of the fluid flow.

The drag coefficient depends on several factors, including the shape and orientation of the object, the speed of the fluid flow, and the properties of the fluid itself. It is typically determined experimentally through wind tunnel tests, computational simulations, or empirical correlations.

Drag coefficient is proportional to { (gravitational force) / (inertial force) } and is used in momentum transfer in general and free settling velocities and resistance to flow calculations in particular. It is normally defined in the following form :




Gravitational acceleration



Characteristic dimension of object



Density of object



Density of surrounding fluid





The drag coefficient provides a convenient way to compare the drag characteristics of different objects or to assess the aerodynamic performance of a particular shape. It is widely used in engineering applications, such as in the design of vehicles, aircraft, buildings, and sports equipment, to optimize performance and minimize energy consumption.

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