In flight mechanics, the skin friction coefficient is a dimensionless parameter representing the ratio of the frictional drag force between an aircraft’s surface and the surrounding air to the dynamic pressure. It characterizes the level of surface roughness or smoothness and is crucial in evaluating skin friction drag, a component of total aerodynamic drag. A lower skin friction coefficient generally corresponds to smoother airflow over the surface, contributing to reduced drag and improved aerodynamic efficiency in flight.
Where:
- A is the Flat plane area in m2
- Φf is the Foam factor Drag,
- Swet is the Wetted area in m2.