Engineering Hydraulics

Question 1

What is viscosity?

Answer 1

A fluids resistance to deformation (flow) due to shear stresses.

Question 2

Re number for open channel laminar flow?

Answer 2

<2000

Question 3

Re number for open channel transitional flow?

Answer 3

2000<Re<4000

Question 4

Re number for open channel turbulent flow?

Answer 4

> 4000

Question 5

Froude number = 0

Answer 5

No flow

Question 6

Froude number < 1

Answer 6

Subcritical flow

Question 7

Froude number = 1

Answer 7

Critical flow

Question 8

Froude number > 1

Answer 8

Supercritical flow

Question 9

Definition of uniform flow?

Answer 9

Flow variables (velocity and depth) are constant in space

Question 10

Definition of non-uniform flow?

Answer 10

Flow variables (velocity and depth) change in space

Question 11

Definition of steady flow?

Answer 11

Flow variables (velocity and depth) at a given point do not change with time (constant flow rate)

Question 12

Definition of unsteady flow?

Answer 12

Flow variables (velocity and depth) at a given point change with time (increase/decrease of flow rate)

Question 13

Hydraulic radius = ?

Answer 13

R = A/P (area/wetted perimeter)

Question 14

In infintely wide channels what doesnt affect flow?

Answer 14

Walls/banks of channel

Question 15

How wide does a channel have to be to ignore effects of walls/banks?

Answer 15

10X its flow depth

Question 16

How do you obtain flow depth from the Manning’s equation?

Answer 16

Trial and error using iterative method

Question 17

Weak Hydraulic Jump

Answer 17

1.7<Fr<2.5

Question 18

Oscillating Hydraulic Jump

Answer 18

2.5<Fr<4.5

Question 19

Steady Hydraulic Jump

Answer 19

4.5<Fr<9

Question 20

Strong Hydraulic Jump

Answer 20

Fr>9

Question 21

What are the conditions for gradually varied flow?

Answer 21

Gradual variations in flow depth and velocity
No surface discontinuities
Component of weight does not balance friction
Geometric slope different from friction slope

Question 22

Mild slope conditions

Answer 22

S<Sc

yn>yc

Question 23

Steep slope conditions

Answer 23

S>Sc
yc>yn

Question 24

Critical slope conditions

Answer 24

S=Sc
yc=yn

Question 25

Horizontal slope conditions

Answer 25

S=0 yn -> infinity

Question 26

Adverse slope conditions

Answer 26

flow depth is critical

Question 27

Driving forces in pipe flow?

Answer 27

Pressure (& sometimes gravity)

Question 28

Reynolds number represents?

Answer 28

Ratio of inertial force to viscous force

Question 29

Re number for pipe laminar flow?

Answer 29

<2300

Question 30

Re number for pipe transitional flow?

Answer 30

2300

Question 31

Re for pipe turbulent flow?

Answer 31

>4000

Question 32

How is turbulent flow charecterised?

Answer 32

Irregular, random, chaotic

Question 33

What equation is used to evaluate head loss in turbulent pipe flow?

Answer 33

Darcy-Weisbach euation

Question 34

What do you use to get pipe friction factor for turbulent flow? (lamda)

Answer 34

Moody diargam

Question 35

How do you get mean flow velocity?

Answer 35

U=Q/A