Flow separation refers to the phenomenon where a fluid flow detaches from a surface, typically due to adverse pressure gradients or changes in flow direction. The formula to predict flow separation is complex and depends on various factors such as Reynolds number, surface roughness, and flow conditions. However, one common criterion used to predict flow separation is the dimensionless parameter called the Reynolds number (Re).
Where:
- ρ is the density of the fluid
- V is the velocity of the flow relative to the surface
- L is a characteristic length (such as the chord length of an airfoil or the diameter of a pipe)
- μ is the dynamic viscosity of the fluid