Fluid Mechanics Full (C4.4) Flashcards
What is fluid mechanics? Give sporting examples.
The study of an object/body travelling through a liquid(water) or gas(air)
E.g. Swimmers travel through water
E.g. Javelin throwers move the javelin through the air
These are either affected by drag or friction
What is a dynamic fluid force?
Forces which affect movement of a body/object through the fluid includes:
- Drag (swimmers,runners,cyclists,skiers)
- Lift (discus, javelin, shot put,archery)
- Friction (runners, cyclists, skiers, snowboarders)
Summarise drag force.
Drag is a resistant force caused by a body travelling through a fluid
- it always acts against the direction of motion
- causes a negative effect on velocity as it slows the object/body to slow down
- consists of a combination of air resistance & friction
Summarise drag force.
Drag is a resistant force caused by a body travelling through a fluid
- it always acts against the direction of motion
- causes a negative effect on velocity as it slows the object/body to slow down
- consists of a combination of air resistance & friction
How and why do performers attempt to minimise drag?
Performers attempt to minimise drag to increase performance over opponents.
To minimise drag
- swimmers wax the entirety of their body and shave their heads to create the most efficient streamline effect maximising their velocity through the water as it affects it less
- cyclists have specialist helmets which cut through the air reducing air resistance which in turn which produce drag
What is surface drag
Friction between the surface of the object and fluid environment
How can surface drag be manipulated?(3 points)
- swimmers specialised smooth suits
-smooth materials create less surface drag - squashing the flesh creates a more streamlined effect increasing velocity
What is form drag?
The impacts of the fluid environments on the object
What are the two factors which affect form drag? Give examples.
Forces affecting the leading edge increase form drag
(having the body in an upright position when cycling)
Forces affecting the trailing edge reduce form drag
(slipstreaming an opponent so that they are in a position where you are their trailing edge enabling you to gain more speed)
What is streamlining?
Streamlining enables the air to flow smoothly reducing fluid drag by incorporating a gradual taper so the the body can move through the fluid effectively and quickly.
What is turbulent flow?
Where the fluid undergoes irregular changes in magnitude and direction
Increases in friction and drag = decrease in velocity
What is laminar flow?
Where layers of the fluid slide smoothly over one another which causes smooth paths making them less resistant to movement.
What are the three factors which increase or decrease drag
- Velocity
- Form drag(cross-sectional area)
- Surface(shape/surface)
How can we increase velocity? (3 points)
The greater the velocity of a body through fluid the greater the drag
Reducing the effects of drag will increase velocity
E.g. Velodrome cyclists have:
-Lightweight bikes with carbon fibre frames which are better aerodynamically
-Cyclists body positions have their heads over the bars to create the perfect streamline effect
-Wear skin-tight clothing to travel faster
How may the cross-sectional area increase/decrease drag?
Having a large cross sectional area will increase drag as the fluid may produce more air resistance or friction to the body or object. This will have a negative impact on the velocity of the object
