1. How can you calculate friction losses

?

Darcy – Weisbach formula:

λ – friction factor
l – distance
d – inner diameter
v – mean velocity
g – gravitational acceleration

2. Draw a resultant characteristics for two pipes

operated in series/ operated parallel

3. Draw a resultant characteristics for two pumps

operated in series/ operated parallel.

4. Define water hammer and maximum increase in

pressure in pipelines.

Sudden change in pressure caused by rapid change in velocity.

Assuming that:



water will be stopped at the distance dl during time period dt just
after sudden closure of check valve



and this phenomenon will be accompanied by:



pressure increase Δp



density increase dp



enlargement of a cross section area by dF

mass accumulated in a pipe at the distance dl (before rapid closure of the
valve “Z”)

and after closure

Principle of conservation of momentum

5. Classify flow in open channels. How can

you

distinguish between varied and uniform flow in

open channels?

Open – channel flow may be:



laminar or turbulent



steady or unsteady



uniform or varied



subcritical or supercritical

Reduction in flow cross section is characterized by a decrease in depth of
flow; since the depth of flow continually varies this type of fluid motion is
termed varied flow.

In varied flow:



Q≠const



F≠const (cross section area differs along the channel; usually
depth varies with distance along the channel)



so velocity v ≠const

6. What does it mean the most efficient cross section

of a channel?

The best hydraulic cross section ensures maximal flowrate at given cross
section area (F=const), slope of the channel bottom (I

d

=const) and roughness

(n=const).

7. Describe characteristics of a critical flow.

a) on the basis of the equation of critical flow

b) apllying Froude’s number

c) comparing the mean depth of water in the channel with velocity head

(h

v

)

d) comparing velocity with its critical value

8. Give two examples of a varied flow in open

channels.



surface water drainage



sewerage networks

9. Classify reactors according to their operation mode

and define basic parameters describing hydraulic

efficiency of reactors operated under continuous

steady flow conditions.

Types of reactors:



batch reactor (BR)



plug flow reactor (PFR)



mixed flow reactor (MFR)

10. What kind of parameters can we get performing

stimulus-response experiments and what can we

use them for?