8. Fluid Mechanics Flashcards
What is fluid mechanics?
A study of forces acting on a body travelling through the air or water.
What is air resistance?
The force that opposes the direction of motion of a body through the air.
What does the force of air resistance act on?
Acts on a body travelling at high velocity through the air such as:
- a cyclist, sprinter, skier, discus or shuttle
What is drag?
The force that opposes the direction of motion of a body through water.
What does drag act on?
A body travelling through water such as:
a swimmer
What affects the magnitude of air resistance and drag?
- velocity
- frontal cross sectional area
- streamlining
- surface characteristics
How does velocity affect the magnitude of air resistance and drag?
The greater the velocity, the greater the air resistance or drag.
How does the frontal cross sectional area affect the magnitude of air resistance and drag?
The larger the frontal cross sectional area, the greater the air resistance or drag.
How does streamlining affect the magnitude of air resistance and drag?
The more streamlined or aerodynamic the shape of the body in motion, the lower the air resistance or drag.
How do surface characteristics affect the magnitude of air resistance and drag?
The smoother the surface, the lower the air resistance or drag.
How is air resistance/ drag reduced in skiing?
- Tripwire suits with wires running through arms/ legs reducing air resistance by 20% by contouring air flow
- Banned as not available for all, now use wind tunnels for fabric development and aerofoils
How is air resistance/ drag reduced in cycling?
- Lightweight carbon fibre bicycles and aerodynamic features
- Aerodynamic riding positions, shoulders forward, high seat positions
- Aerodynamic helmets and smooth lycra skin suits and aerofoils
How is air resistance/ drag reduced in swimming?
- Strokes, swimsuits, streamlined positions, dives, turns
