Part 3: Dimensional Analysis and Similitude

Question 1

__________ is the theory and art of predicting prototype conditions from model observations

Answer 1

Similitude ( or Similarity)

Question 2

Dimensional Analysis is based on _________

Answer 2

Fourier’s principle of dimensional homogeneity and the Buckingham Pi Theorem

Question 3

Determination of PI terms by inspection is based on the fact that each term is ____________

Answer 3

Dimensionless

Question 4

Reynolds number is a radio of ______

Answer 4

inertia force to viscous force

Question 5

What is the Froude Number

Answer 5

a characteristic length, usually taken to be the depth of the flow.

Question 6

Euler’s number is a ratio of __________

Answer 6

Inertia force to pressure force

Question 7

Cauchy Number is the ratio of __________

Answer 7

Inertia force to compressibility force

Question 8

Weber number is the ratio of___________

Answer 8

Inertia force to surface tension force

Question 9

Strouhal number is a ratio of __________

Answer 9

Inertia (Local) force to Inertia (Convective ) force

Question 10

What are the Three Basic Laws of Similitude?

Answer 10

1) Geometrically Similar (Shape)
2) Kinematic Similarity (Velocity, Acceleration, Flow pattern)
3) Dynamic Similarity (Force)

Question 11

What are the three types of model study?

Answer 11

Enclosed, flow in a pipe
Enclosing Flow, flow around an immersed body
Free Flow, flow in a river

Question 12

Drag on a submerged body, such a as ship, is from two sources. What are they?

Answer 12

Form drag and skin friction drag. Form is related to the formation of the object. Skin is related to the boundary resistance.