Aerodynamics Practice Test: Boundary Layers, Laminar & Turbulent Boundary Layers, Navier Stokes Solutions — Flashcards

Boundary layer equations are a simplified form of the Navier-Stokes equations. The solution to the boundary layer equations for steady flow over a flat surface parallel with the oncoming flow is called the Blasius solution. 

Boundary layers can be classified into different types:
Laminar boundary layer: Flow inside this layer is smooth and takes place in layers. Laminar boundary layers are formed when the Reynolds number is low.
Turbulent boundary layer: Flow inside this layer is more chaotic and is characterized by active mixing of the fluid and momentum across several layers. Turbulent boundary layers are formed only at high Reynolds number. 

Laminar boundary layers usually form near the leading edge or nose of a body. The flow in a laminar boundary layer is smooth and steady. Turbulent boundary layers are formed when the laminar boundary reaches a certain age (Reynolds number) and becomes unstable.