2. Applications of Bernoulli’s Principle

3. faster speed slower speed more pressureless pressure If no change in height: P + ½ρv 2 = constant P+ ρgy + ½ ρv 2 = constant

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

5. Motion of fluid energykinetic Pressure in fluidenergy potential KE + PE is constant

6. d d/4 v If incompressible fluid (density = ρ), change in pressure?

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

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

10. DRAG THRUST LIFT GRAVITY

11. v1v1 v2v2 Net force on wing? ½ Aρ(v 2 2 – v 1 2 ) ρ air = 1.29 kg/m 3

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

13. Racecar Spoiler provides better traction and avoids lift

14. Wind over a roof v v = 0 p atm p roof P atm = P roof + ½ ρv 2

15. slow air speed fast air speed

16. Curve Ball

18. Golf ball dimples

19. Winds over a mountain

20. Shower Curtain

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