Week 10

Question 1

Why do quantities between model and prototype disagree?

Answer 1

Measurement Effects
Model Effects
Scale effects

Question 2

What type of similarity is necessary for a perfect model-prototype similarity?

Answer 2

Mechanical Similarity, which is made up of:

Geometric similarity
Kinematic similarity
Dynamic Similarity

Question 3

How is inertial force represented in fluid dynamics?

Answer 3

(rho)(L^2)(V^2)

Question 4

How is gravitational force represented in fluid dynamics?

Answer 4

(rho)(L^3)(g)

Question 5

How is viscous force represented in fluid dynamics?

Answer 5

(υ)(L^3)(g)

Question 6

How is surface tension force represented in fluid dynamics?

Answer 6

sigma*L

Question 7

How is elastic compression force represented in fluid dynamics?

Answer 7

E*(L^2)

Question 8

How is pressure force represented in fluid dynamics?

Answer 8

p*(L^2)

Question 9

Define Froude number, F.

Answer 9

(inertial force/gravity force)^0.5

Question 10

Define Reynolds number, R.

Answer 10

inertial force/viscous force

Question 11

Define Weber number, W.

Answer 11

inertial force/surface tension force

Question 12

Define Cauchy number, C

Answer 12

inertial force/elastic force

Question 13

Define Euler number, E

Answer 13

pressure force/inertial force

Question 14

What are scale effects due to with regards to F?

Answer 14

reduced flow velocity

Question 15

What are scale effects due to in R?

Answer 15

larger viscous losses in model

Question 16

What are scale effects due to in W?

Answer 16

Too large air bubbles and faster air detrainment
Wave celerit of short wave is affected
Reduced discharge for small water depths

Question 17

What are scale effects due to in C?

Answer 17

structure interacting with water behaves too stiff and strong.
Water and air are too hard in the model

Question 18

What are scale effects due to in E?

Answer 18

Cavitation can not be observed in model if atmospheric pressure is not scaled

Question 19

What is the scale factor for length?

Answer 19

λ

Question 20

What is the scale factor for mass?

Answer 20

(rho-prototype/rho-model)*(λ^3)

Question 21

What is the scale factor for mass moment of inertia (J) ?

Answer 21

(rho-prototype/rho-model)*(λ^5)

Question 22

What is the scale factor for area moment of inertia?

Answer 22

λ^4

Question 23

What is the scale factor for water velocity?

Answer 23

λ^0.5

Question 24

What is the scale factor for air velocity?

Answer 24

(λ^0.5)*(1/Beta)

Question 25

What is the scale factor for acceleration?

Answer 25

1

Question 26

What is the scale factor for time?

Answer 26

λ^0.5

Question 27

What is the scale factor for frequency?

Answer 27

λ^(-0.5)

Question 28

What is the scale factor for angle?

Answer 28

1

Question 29

What is the scale factor for force?

Answer 29

(rho-prototype/rho-model)*(λ^3)

Question 30

What is the scale factor for moment?

Answer 30

(rho-prototype/rho-model)*(λ^4)

Question 31

What is the scale factor for stiffness?

Answer 31

(rho-prototype/rho-model)*λ

Question 32

What is the scale factor for stress?

Answer 32

(rho-prototype/rho-model)*λ

Question 33

What is the scale factor for power?

Answer 33

(rho-prototype/rho-model)*(λ^3.5)

Question 34

What is the scale factor for thrust coefficient?

Answer 34

(rho-prototype/rho-model)*(Beta^2)