11.4: Fluid Mechanics Flashcards
1
Q
Drag force definition:
A
- the force that acts in the opposite direction to motion
2
Q
Streamlining definition:
A
-involves shaping a body so it can move as effectively and quickly through a fluid as possible.
3
Q
Lift force definition:
A
- causes a body to move perpendicular to the direction of travel.
4
Q
Angle of attack definition:
A
- the tilt of a projectile relative to the air flow.
5
Q
Bernoulli principle definition:
A
- where air molecules exert less pressure the faster they travel and more pressure when they travel slower.
6
Q
What is fluid mechanics?
A
- the study of an object or human body that travels through any liquid or gas.
- for example, a swimmer travels through water and a tennis ball through the air. They are both slowed down by either friction or drag.
7
Q
What is dynamic fluid force?
A
- fluid dynamics is concerned with the movements if liquids and gases.
- drag and lift force are dynamic fluid forces.
- these two forces have an effect on a variety of sports such as cycling and sprinting.
8
Q
What are the two dynamic fluid forces?
A
- drag and lift
9
Q
What is drag force?
A
- slows something down.
- resistance force caused by motion of body travelling through a fluid.
- acts in opposition to the direction of motion and therefore negative effect on velocity.
10
Q
What are the two types of drag force?
A
- surface drag
- form drag
11
Q
What is surface drag?
A
- relates to friction between surface of an object and the fluid environment.
- swimmers west specialised clothing and shave body hair off from arms and torso to reduce surface drag
12
Q
What is form drag?
A
- relates to impact of fluid environment on an object.
- sometimes referred to as ‘shape drag’
- FD relates to streamlining and swimmer has to create thinnest and straightest form as they move through the water.
13
Q
What are the factors reducing and increasing drag?
A
- velocity of the moving body
- cross-devotional area of the moving body
- Shape and surface characteristics of moving body.
14
Q
How does velocity have an effect on drag?
A
- grater the velocity of a body through a fluid, the grater the drag force.
- d.g. A cyclist or sprinter will experience air resistance in their competition which increases drag
15
Q
How does the cross-sectional area affect drag?
A
- large cross-sectional area increases drag.
- e.g. in Tour de France, competitors reduce cross-sectional area by crouching low over the handlebars, rather than sitting upright.
