The coefficient of drag of an airfoil, denoted (Cd), is a dimensionless measure of the aerodynamic drag experienced by the airfoil as it moves through a fluid, typically air. It quantifies the resistance encountered due to the airfoil’s shape and flow conditions. It’s defined as the ratio of drag force to dynamic pressure and reference area. Lower Cd values signify better aerodynamic efficiency. Engineers use it to compare and optimize airfoil designs for improved performance. The formula to calculate Coefficient of drag of an airfoil as follows:
Where:
- D is the Drag force in N
- b is the span in m,
- q∞ is the Dynamic pressure in Pa,
- C is the mean chord in m.