330
9 Experimental Methods in Fluid Mechanics
a N U'
l?
1.0
......
~ 0.8
'-'
~
0.6
0.4
0.2
0.0
-0.2
-0.4
-0.6
0
4
8
12
16
Time't(s)
b -- 0.5
8
'-'
00
0.4
0.3
0.2
0.1
0.0
o
2
3
4
5
Frequency ro(rad / s)
Fig. 9.5: Frequency spectra: a typical normalized autocorrelation function for surface waves, b corresponding frequency spectral density
9 Experimental Methods in Fluid Mechanics
a N U'
l?
1.0
......
~ 0.8
'-'
~
0.6
0.4
0.2
0.0
-0.2
-0.4
-0.6
0
4
8
12
16
Time't(s)
b -- 0.5
8
'-'
00
0.4
0.3
0.2
0.1
0.0
o
2
3
4
5
Frequency ro(rad / s)
Fig. 9.5: Frequency spectra: a typical normalized autocorrelation function for surface waves, b corresponding frequency spectral density