Lec 1 2 3 FLOW IN PIPES Dr

Lec 1, 2, 3 FLOW IN PIPES Dr. Zainab Talib Al-Sharify Email: zainab_talib 2009@yahoo. com

Summary Ø Lecture 1 § Introduction § Real fluid flow § viscosity Ø Lecture 2 § Reynolds number § Critical Reynolds number

Summary Ø Lecture 3 § Laminar and turbulent flow v Turbulent flow v Characteristic of turbulent flow v Shear Stress due to turbulence v Prandatl approach for limiting length v Jon Karmn approach

Real fluid flow

Reynolds number

Reynolds number

Critical Reynolds number

Laminar and turbulent flow laminar flow or streamline flow in pipes (or tubes) occurs when a fluid flows in parallel layers, with no disruption between the layers. At low velocities, the fluid tends to flow without lateral mixing, and adjacent layers slide past one another like playing cards. There are no cross-currents perpendicular to the direction of flow, nor eddies or swirls of fluids. Diffusion mixing can be slow however if the diameter of the pipe of tube is small then this diffusive mixing can be very significant.

Laminar and turbulent flow Turbulent flow is a flow regime characterized by disarranged property changes. This includes rapid variation of pressure and flow velocity in space and time. Flows at Reynolds numbers larger than 4000 are turbulent, Flow in the range of Reynolds numbers 2100 to 4000 and known as transition.

Introduction to Turbulence & Turbulence modeling https: //www. youtube. com/watch? v=G 32 LXe. Cx 7 H 0

Laminar and turbulent flow

H. W Lec 1: Questions 7. 4 - 7. 9 Lec 2, 3: Questions 7. 10 – 7. 25

References

Dr. Zainab Talib Al-Sharify Thank you!