How to use the calculator
- Enter the drag force acting on your object in newtons (N)
- Set the air density (default is standard sea level: 1.225 kg/m³)
- Input the velocity of the flow relative to the object in meters per second (m/s)
- Specify the reference area in square meters (m²) - typically the frontal area for blunt objects or cross-sectional area for streamlined objects
- Click the "Calculate" button to compute the drag coefficient
Understanding Drag Coefficient
The drag coefficient (Cd) is a dimensionless quantity that quantifies the resistance of an object to being moved through a fluid. It depends on the shape of the object, the Reynolds number, and the surface roughness.
The formula used in this calculator is:
Cd = Fd / (0.5 × ρ × v² × A)
Typical Drag Coefficient Values
- Airplane (streamlined body): 0.025 - 0.04
- Sphere: 0.4 - 0.5
- Cylinder (flow parallel to axis): 0.8 - 1.2
- Square: 1.0 - 2.0
- Car (modern): 0.2 - 0.4
Applications
This calculator is useful in various fields including:
- Aerospace engineering
- Automotive design
- Fluid dynamics analysis
- Wind tunnel testing
- Sports equipment design (e.g., golf balls, sails)