Reynolds Expression for Turbulent Shear Stress
In turbulent flow, the Reynolds expression for turbulent shear stress is used to calculate the additional stress caused by turbulence. It’s written as:
τ = ρu‘v‘
where,
- τ is the turbulent shear stress.
- ρ is the fluid density.
- u and v are the fluctuations in the velocity components in the flow direction and perpendicular to the flow direction, respectively.
- The overbar denotes averaging over time.
This formula helps calculate how much extra force is generated by the chaotic swirling motions in turbulent flow.
Laminar and Turbulent Flow
Laminar flow and turbulent flow describe the movement patterns of fluids. Laminar flow is characterized by smooth, orderly layers of fluid sliding over one another without mixing, ideal for scenarios where minimal resistance is desired. Turbulent flow features chaotic, swirling patterns with irregular fluctuations, often causing increased energy dissipation and mixing.