Related Resources: fluid flow
Circular Flat Disk Drag Coefficient and Drag Equation
Air Flow Drag, Drag Coefficient Equation and Calculators
Fluids Design and Engineering Data
Air Flow Drag and Drag Coefficient Equations and Calculator
The drag coefficient (nondimensional drag) is equal to the drag force divided by the product of velocity pressure and frontal area. The velocity may be that of the object through the air (or any other gas) or the air velocity past a stationary object. Coefficients are given for a number of geometrical shapes and also for cars, airships and struts.
Drag Equation:
Illustration

Description

L / d

C_{d}

R_{e} / 10^{4}

Frontal Area

Circular Flat Disk Drag



1.12

100

π d^{2 }/ 4

Where:
D = Drag (N);
C_{d} = Drag Coefficient (unit less);
ρ = fluid density (kg/m^{3});
A =frontal area (m^{2});
V = fluid velocity (m/sec);
d = Diameter (m);
R_{e} = Reynolds Number (unit less)
Density of air = 1.225 kg/m^{3}