1. CE 230-Engineering Fluid Mechanics Lecture # 4and5 Fluid properties (2)

2. Examine velocity distribution in pipe

3. Viscosity Consider two plates separated be a thin film of fluid. The lower plate is fixed and the upper is moving with a constant velocity. Investigate what is happening in the fluid in terms of flow or stresses.

4. Viscosity No slip boundary condition Relation between shear stress and velocity gradient Classification of fluids

5. Mechanisms of fluid resistance to shear stress Particle cohesion Transfer of molecular momentum Influence of temperature on viscosity

6. Units of viscosity Dynamic viscosity absolute viscosity viscosity Kinematic viscosity

7. Influence of temperature on viscosity

8. Classification of fluids according to relation of shear to strain rate

9. Problems on viscosity Board sliding on an inclined surface separated by a thin film of oil Is there a shear stress in the film? let’s calculate the terminal velocity

11. Problem # 34

12. Problem # 39 Calculate the weight of piston given : Terminal velocity μ Spacing between piston and cylinder Piston dimensions

13. Problem 2.39

14. Problem 2.41