Drag Coefficient Formula
Following is the formula used to calculate the drag coefficient:
\begin{array}{l}D=\frac{C_{d}*\rho *V^{2}A}{2}\end{array}
Where,
Cd is the drag coefficient
ρ is the density of the medium in kg.m-3
V is the velocity of the body in km.h-1
A is the cross-sectional area in m2
Solved Examples
Question 1. A car travels with a speed of 80 km.h-1 with a drag coefficient of 0.25. If the cross-sectional area is 6 m2, calculate the drag force.
Solution:
Given:
Velocity, V= 80 km.h-1
Drag coefficient, Cd= 0.25
Cross-sectional area, A= 6 m2
Density of fluid, ρ =1.2 kg.m-3
The drag force is given as:
\begin{array}{l}D=\frac{C_{d}*\rho *V^{2}A}{2}\end{array}
\begin{array}{l}D=\frac{0.25*1.2*6400*6}{2*3600}\end{array}
D=1.6 N