20. Introduction to Turbulent Flow
The chapter explores the dynamics of turbulent flow, detailing the contrast between laminar and turbulent profiles, introducing the concept of shear stress in fluid dynamics, and discussing key layers in turbulent flow. It emphasizes using practical examples, including the calculation of shear stress at the wall and the analysis of boundary characteristics such as roughness and smoothness.
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Sections
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What we have learnt
- Turbulent flow has a fuller velocity profile compared to laminar flow, impacting shear stress at the wall.
- The Prandtl mixing length theory provides a framework for understanding turbulent velocity profiles.
- Boundary characteristics are classified based on surface irregularities, affecting flow dynamics and roughness.
Key Concepts
- -- Turbulent Flow
- A type of fluid flow characterized by chaotic changes in pressure and flow velocity, resulting in a non-linear velocity profile.
- -- Viscous Sublayer
- The thin layer of fluid adjacent to a boundary where viscous forces dominate and the flow profile is nearly linear.
- -- Shear Stress (tau)
- The stress component parallel to the surface of a material, significant in determining fluid movement in pipes.
- -- Velocity Defect Law
- A relationship expressing the difference between maximum velocity and actual velocity within a turbulent flow regime.
- -- Rough Boundary
- A boundary condition characterized by surface irregularities that influence the flow profile significantly, especially when the height of irregularities exceeds the viscous sublayer thickness.
Additional Learning Materials
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