Skin friction drag (Cf) is a concept used in fluid dynamics to quantify the drag force experienced by a solid body moving through a fluid, particularly in the context of aerodynamics. It specifically refers to the drag force resulting from the viscous shear stress at the surface of the body due to the fluid’s viscosity.
- Cf* is the skin friction drag coefficient,
- Df is the skin friction drag force acting on the surface of the body,
- ρ* is the fluid density,
- ue is the velocity at the edge of the boundary layer (external flow velocity),
- S is the reference area on which the drag force is based.