Part 6: Open Flow Channel

Question 1

Two types of channel?

Answer 1

Prismatic: regular cross section

Non-prismatic: irregular cross section

Question 2

Laminar flow in a channel is a max of …

Answer 2

Re < 500

Question 3

What is the turbulent flow in a channel?

Answer 3

Re > 12500

Question 4

What is the formula for hydraulic radius?

Answer 4

R=A/P

Question 5

Three flow classifications?

Answer 5

Subcritical Fr<1
Supercritical Fr>1
Critical Fr=1

Question 6

If V

Answer 6

Subcritical

Question 7

If V=c flow is _____

Answer 7

Critical

Question 8

For V>c the flow is _______

Answer 8

Supercritical

Question 9

What is specific energy?

Answer 9

The energy of flow defined with respect to the bed of the channel

Question 10

T or F. E is a minimum at the critical depth

Answer 10

True

Question 11

T or F. If the flow is uniform then dy/dx=0.

Answer 11

True

Question 12

For uniform flow, the loss in potential energy equals…

Answer 12

The energy dissipated by friction

Question 13

What does chezy equation consider?

Answer 13

Uniform flow in a channel which is sloped

Question 14

Is chevys coefficient is dimensionless?

Answer 14

No units of (sqrt(L))/T

Question 15

Manning’s coefficient reflects what?

Answer 15

• Roughness of the pipe

- dimensions are (T/L^1/3)

Question 16

Channels of circular cross section have a unique attribute with respect too?

Answer 16

Max velocity and discharge

Question 17

Most efficient hydraulic sections?

Answer 17

• semi circle
• trapezoid
• triangle

Question 18

What is GVF?

Answer 18

Gradually varied flow

Question 19

What is an occurrence of GVF?

Answer 19

• changes in channel geometry
• changes in channel resistance
• changes in channel slope
• existence of an obstruction(eg dam)

Question 20

What are the 5 types of slopes?

Answer 20

Mild Fr<1
Critical Fr=1
Steep Fr>1
Horizontal So=0
Adverse So<0

Question 21

How to determine slope for uniform flow?

Answer 21

Yn>Yc slope mild flow subcritical
Yn=Yc slope critical flow critical
Yn

Question 22

What is RVF?

Answer 22

Rapidly varied flow

Question 23

The occurrence of RVF can result from?

Answer 23

• Abrupt changes in channel geometry

- Interface between supercritical and subcritical

Question 24

Applications of weirs?

Answer 24

Water treatment plants
Research
Irrigation systems

Question 25

Types of weirs?

Answer 25

• Sharp-crested
• broad crested weir
• zero height weir
• v notch
• special types