Boimechanics - Fluid Mechanics

Question 1

Define drag force

Answer 1

A force that acts in the opposite direction to motion

Question 2

Name the 2 types of drag

Answer 2

Surface drag
Form drag

Question 3

Define surface drag

Answer 3

Relates to friction between the surface of an object and the fluid environment. It can sometimes be referred to as skin drag.

Question 4

Define form drag

Answer 4

Relates to the impact of the fluid environment on an object. It is sometimes referred to as ‘shape drag’. The forces affect the leading edge of an object.

Question 5

Name 3 factors that affect drag

Answer 5

Velocity of the object
Cross-sectional area of the object
Shape/surface characteristics of the object

Question 6

Explain how velocity of the object affects drag

Answer 6

The greater the velocity of a body through a fluid, the greater the drag force.

Question 7

Explain how cross-sectional area of an object affects drag

Answer 7

A large cross-sectional area results in a greater amount of drag.

Question 8

Explain how shape/surface characteristics of an object affects drag

Answer 8

A more streamlined, aerodynamic shape reduces drag.

Question 9

In relation to the Bernoulli Principle, what shape does a discus fly in?

Answer 9

Aerofoil

Question 10

In relation to discus, what is the appropriate angle of attack for a discus?

Answer 10

25-45 degrees

Question 11

When a discus is in flight, is there an area of high pressure below or above it?

Answer 11

Below

Question 12

When a discus is in flight, is there an area of low pressure below or above it?

Answer 12

Above