Fluid mechanics: drag Flashcards
What is fluid mechanics?
The study of fluids in a static or a dynamic state.
What is fluid dynamics?
The study of forces on fluids
What are fluid forces?
Drag and lift
What are fluid forces involved in?
They play a massive role in sports like cycling, swimming, and sprinting.
They also affect certain projectiles such as balls, discus’s, and javelins
What is a drag force?
A resistance force that slows a body or object down.
It acts in opposition to movement and therefore has a negative affect on velocity
What are the two types of drag?
Surface and form drag
What is surface drag?
Caused by friction when the fluid environment passes over the surface of an object or the body.
What is form drag?
Basically how the size and shape of an object/body can affect how water/air pass over it.
What do factors that affect the leading edge do?
Increase drag
What do factors that affect the trailing edge do?
Reduce drag
What is streamlining?
Altering a body/object so that it passes through the air/water more efficiently.
Give 4 examples of how to reduce surface drag
- Wearing lycra suits
- Shaving whole body (reduce time by 3 mins in Tour de France race)
- Bikes have smooth, glossy paint
- Glossy paint on helmets
What is drafting?
A large form drag that reduces turbulent air for anything behind it.
This is called a slipstream
Give 3 examples of how to reduce form drag
- Performers tucking their body whilst skiing or cycling
- Caps on bike wheels to reduce turbulent air
- Javelin - small leading and trailing edge
How much does drafting reduce drag?
30cm between bikes will lead to a 30% reduction in drag
