Drag Equation Calculator:
Enter the values of fluid density, ρ(kg/m3), velocity, v(m/s), cross-sectional area, A(m2) and drag coefficient, cd to determine the value of Drag Force, F(N).
Drag Equation Formula:
The drag equation is a fundamental principle in fluid dynamics used to calculate the resistive force (drag) experienced by an object moving through a fluid, such as air or water. Drag is the opposing force that acts on an object, impeding its motion relative to the surrounding fluid. The drag force depends on various factors, including the density of the fluid, the velocity of the object, the cross-sectional area of the object, and the drag coefficient.
The drag coefficient is a dimensionless quantity that reflects the object’s shape and surface characteristics, indicating how streamlined it is. A larger cross-sectional area increases drag because more fluid is displaced, while higher velocity exponentially increases drag due to increased interaction with the fluid.
The formula accounts for the dynamic pressure of the fluid, which is proportional to the square of the velocity, and is scaled by the fluid’s density and the object’s drag coefficient and area. This equation is vital in designing aerodynamic and hydrodynamic objects, such as airplanes, cars, and ships, to reduce resistance and optimize efficiency.
Drag Force, F(N) in Newtons equals half the product of the fluid density, ρ(kg/m3) in kilograms per cubic metres, the square of the velocity, v(m/s) in metres per second, the cross-sectional area, A(m2) in square metres and the drag coefficient, cd.
Drag Force, F(N) = 0.5 * ρ(kg/m3) * v2(m/s) * A(m2) * cd
F(N) = drag force in Newton, N.
ρ(kg/m3) = fluid density in kilograms per cubic metres, kg/m3.
v(m/s) = velocity in metres per second, m/s.
A(m2) = cross-sectional area in square metres, m2.
cd = drag coefficient.
Drag Equation Calculation:
- A car has a drag coefficient of 0.3, a cross-sectional area of 2.5m2, traveling at a velocity of 30 m/s in air with a density of 1.225 kg/m3. Calculate the drag force.
Given: ρ(kg/m3) = 1.225kg/m3, v(m/s) = 30m/s, A(m2) = 2.5m2, cd = 0.3.
Drag Force, F(N) = 0.5 * ρ(kg/m3) * v2(m/s) * A(m2) * cd
F(N) = 0.5 * 1.225 * 302 * 0.5 * 0.3
F(N) = 82.68N.
- An object with a drag coefficient of 1.2 and cross-sectional area of 1m2 experiences a drag force of 100N in a fluid with density of 1 kg/m3. Calculate the velocity.
Given: ρ(kg/m3) = 1kg/m3, F(N) = 100N, A(m2) = 1m2, cd = 1.2.
Drag Force, F(N) = 0.5 * ρ(kg/m3) * v2(m/s) * A(m2) * cd
v(m/s) = √( F(N) / 0.5 * ρ(kg/m3) * A(m2) * cd)
v(m/s) = √(100 / 0.5 * 1 * 1 * 1.2)
v(m/s) = √166.67
v(m/s) = 12.91m/s.