Boundary Layer

Definition

The Boundary Layer is the thin region of fluid near a solid surface where viscous effects are significant and the flow velocity changes from zero at the wall (no-slip condition) to the free-stream velocity.

Scaling

$\delta/L \sim Re^{-1/2}$ where $\delta$ is the boundary layer thickness.

Relationships

• Related: Reynolds Number, Displacement Thickness

See Also

• Boundary Layers (Concept) — Overview of boundary layer types and theory