.No.: 04

Class arrangement: 8 class hours: theory class √ experiment class □ exercise class □ practice class □ others □

Theme (teaching chapter or theme):

Chapter IV Flow Resistance and Energy Loss

Requirements for teaching purposes (divided into three levels: mastery, familiarity and understanding):

Objective: To make students understand two types of actual fluid flow, namely, flow resistance and head loss, and to master the analysis and calculation methods of loss along the way and local loss.

Basic requirements: Understand the two flow patterns of actual liquid, the causes of flow resistance and head loss, and the concepts of boundary layer and flow resistance. Master the basic equation of uniform flow, the calculation methods of resistance coefficient along the pipe, head loss along the pipe and local head loss of laminar and turbulent flow, and understand the important concepts such as equivalent roughness, equivalent diameter and hydraulic radius.

Teaching content (Note: * Key # Difficulties? Doubt):

The teaching content and class time allocation of each section in this chapter:

4- 1 0.5 class hour for two kinds of flow resistance and head loss

4-2 laminar flow, turbulence and Reynolds number 1.5 hours

4-3 Laminar flow in circular tube 1 class hour

4-4 Characteristics of Turbulence and Turbulent Shear Stress 1 class hour

4-5 Nicholas's experiment 1 hour

4-6 concept of equivalent roughness and calculation of λ 1 class hour of industrial pipeline

4-7 concept of equivalent diameter and loss of non-circular tube along the way 1 hour

4-8 Local loss of pipeline flow 1 class hour

* * * 8 class hours.

The emphases and difficulties of the teaching content in this chapter:

* The discrimination of two flow patterns of actual liquid, the basic equation of uniform flow, the velocity distribution of laminar and turbulent flow in circular tube, the calculation of resistance coefficient and head loss along the way, and the calculation of local head loss.

# Characteristics of loss along the route and local loss, concepts of equivalent roughness and equivalent diameter, calculation of turbulent resistance coefficient along the route.

Deepen and broaden the teaching content of this chapter;

Deepening: the foundation of theory of turbulence, the application of theory of turbulence, the difference and connection between N-S equation and Reynolds stress equation.

Broadening: the development of modern turbulence model.

Teaching methods, means and media:

Teaching method: teaching-questioning-teaching-exercise class-experiment

Attention should be paid to the distinction between turbulent flow and laminar flow, and the selection of empirical formulas for velocity distribution, shear stress distribution and turbulent resistance coefficient in circular tubes.

Teaching media: multimedia combined with blackboard writing

Discussion, thinking and homework:

Discussion: 1) How is turbulence formed?

2) Why can Re number be used as the only criterion to judge the flow pattern, but critical velocity can't?

2. Homework:

Exercise: 4-2, 4-5, 4-8, 4-9, 4- 10, 4- 14, 4- 16, 4- 19, 4-2/kloc-0.