Question

What are the similarities between drag coefficient and friction factor?

Answer 1

drag coefficient is given by the following equation

Fd is the drag force, which is by definition the force component in the direction of the flow velocity

is the mass density of the fluid

is the flow speed of the object relative to the fluid

is the reference area

• f is the local Fanning friction factor (dimensionless)
• is the local shear stress
• is the bulk flow velocity
• is the density of the fluid

the similarities are both are defined as the ratio of shear stress to the product of density, square of the velocity and 0.5

where Fd/A is the shear stress of the drag.

Tw is the wall shear