1. Applications of Bernoulli’s Principle

2. Demo’s: Ping Pong Ball in funnel Ping Pong Ball in air stream Paper parallel paper Note: With demos 1.5 periods

3. slower speed
faster speed
more pressure
less pressure

4. As the speed of a fluid increases,
the pressure in the fluid decreases.
P α 1/v

5. As the speed of a fluid increases,
the pressure in the fluid decreases.
P α 1/v

6. Bernoulli & Flight
Bernoulli’s Principle is what allows birds and planes to fly.
The secret behind flight is ‘under the wings.’

8. On top: greater air speed and less air pressure
AIRFOIL
On top: greater air speed and
less air pressure
On bottom: less air speed and
more air pressure

9. v2 v1
Net force on wing?

10. LIFT
THRUST
DRAG
GRAVITY

11. Spoiler – airfoil reversed
less air speed
more pressure
greater air speed
less pressure
net force: downward

12. Spoiler provides better traction and avoids lift
Racecar
Spoiler provides better traction
and avoids lift

13. Wind over a roof
Patm = Proof + ½ ρv2 v
proof
v = 0
patm

14. slow air speed
fast air speed

15. Curve Ball

17. Golf ball dimples

18. Winds over a mountain

19. Shower Curtain

20. Review
Ping pong balls?
Cardboard walls?
Paper?
Baseball?

21. Instability in passing – Trailers?
Trains passing each other?

22. Atomizer – As air passes at top of tube,
the pressure decreases and fluid is drawn up
the tube.

24. 2009 Darwin Award

25. 2009 Darwin Award
(15 December 2009, Germany) A U2 subway driver found a body laying besides the underground tracks in Berlin. Because there was no video surveillance camera at that location, it took police two days to reconstruct what had happened. Apparently Yasin A., 22, was alone in the subway car when he decided it would be a brilliant idea to destroy one of the windows. By swinging feet forward from a handrail into the window, he not only managed to burst the glass but also succeeded in being sucked out of the moving train, and was left dead on the tracks. He was alone in the compartment at the time; if an observer had been present, perhaps the young underground rider would not have engaged in destructive nonsense that led to his senseless death.