Surface Drag (skin friction):

Fluid particles near the body are slowed due to frictional forces, creating a boundary layer. This is mainly a factor during laminar flow.

Factors that affect surface drag include:

  1. Relative velocity
  2. Surface area
  3. Surface roughness
  4. Fluid viscosity

The smoother the surface, the less surface drag...yet what about a golf ball?

Why the roughened surface?