2. Understand the study of Fluid Mechanics
Identify fluid forces of interest
• Drag
• Lift
• Buoyancy
Understand The Magnus effect
Choose the topics for your presentation

3. Fluid Mechanics: the study of forces that
develop when an object moves through a
fluid medium.
 Two fluids of interest….
 Water
 Air

4. In some cases, fluid forces have little effect
on an object’s motion (e.g., shot put)
•In other cases, fluid forces are significant
– badminton, tennis, swimming, cycling, etc.
• Major fluid forces of interest:
 Buoyancy
 Drag
 Lift

5. Drag force acts in a direction that is
opposite of the relative flow velocity.
– Affected by cross-section area (form drag)
– Affected by surface smoothness (surface
drag)
• The lift force acts in a direction that is
perpendicular to the relative flow.
– The lift force is not necessarily vertical.

9. Resistive force acting on a body moving through a
fluid (air or water). Two types:
•Surface drag: depends mainly on smoothness of
surface of the object moving through the fluid.
•shaving the body in swimming; wearing racing
suits in skiing and speed skating.
•Form drag: depends mainly on the cross-
sectional area of the body presented to the fluid
• cyclist in upright v. crouched position
• swimmer: related to buoyancy and how high
the body sits in the water.
Drag

11. How Would be reduce From
Drag???
•Change the shape of an object
•Smoother surface
•Higher altitude – air density is
lower

12. Mathematically Drag Force can be
expressed by:
Where
= Drag force
= Coefficient of drag
= fluid density
= Area of the object
= Relative velocity of the object
with respect to the fluid

13. Sometimes a rougher
surface will decrease drag.
When turbulent flow occurs
at the leading surface of
the object, form drag is
decreased.
The turbulent air
surrounding the object is
carried along with the
object. The flow of the rest
of the flow is laminar and
does not exert much drag
force on the object.

16. Mathematically Lift Force can be expressed
by:
Where
= fluid density
= Area of the object
= Relative velocity of the object
with respect to the fluid
= Lift force
= Coefficient of lift

17. The Magnus effect
In 1852, the German Scientist, Gustav Magnus,
noticed that lift forces are also generated by
spinning balls. This effect is called the Magnus
effect.
A lift force caused by a spin is called a Magnus
force.
A golf shot generating back spin would
cause what?
A tennis shot with top spin would cause the
ball to do what?

19. , fade, draw

23. Your Presentations….
You must produce a seminar on fluid mechanics in a sporting context.
This must be presented in 2 parts:
1) An introduction to fluid mechanics in general. This section must
include and demonstrate a sound understanding of one of the relevant
factors in fluid mechanics, (e.g. Laminar boundary layer, drag,
buoyancy, lift etc.) Giving particular reference to terms that are
relevant to the second part of the your piece of work.
2) A sport specific example of fluid mechanics in sport. This should
contain the main bulk of your work. You must consider the factors which
affect your chosen activity and show a sound understanding of the factors
that affect it. Examples in the past have included dimples on a golf ball,
the boomerang, swimming suits, a curling football and Formula .
This seminar must last at least 5-7 minutes long and you must submit
you’re a copy of your seminar prior to the session. Do this by uploading
your presentation to pbworks.

24. Understand the study of Fluid Mechanics
Identify fluid forces of interest
• Drag
• Lift
• Buoyancy
Understand The Magnus effect
Choose the topics for your presentation
Conclusion