Aerodynamic Structural Noise - Hybrid Anisotropic Materials for Wind Power Turbine Blades - page 204

Sound Pressure Change with Different Frequencies

120

Column A
Column B
Column C

100

80

60

40

20

0

1 2 3 4 5 6 7 8 9 10 11

Frequencies, Hz

FIGURE 7.4
Sound. pressure. change. with. different. frequencies.. (From. Rogers,. A.. L.. 2006.. University. of.
Massachusetts..Online.at:.www.renewableenenergy.world.com..With.permission.).

Measuring Sound Noise

20000

Column A
Column B
Column C
Column D

15000

10000

5000

0

1 2 3 4 5 6 7 8 9 10 12

Response, DB

-5000

FIGURE 7.5
Measuring. sound.. (From. Rogers,. A.. L.. 2006.. University. of. Massachusetts.. Online. at:. www.
renewableenenergy.world.com..With.permission.)