Forschungszentrum Karlsruhe
in der Helmholtz-Gemeinschaft
Offshore Wind and Turbulence Profiles from the FINO1-Mast
Matthias Türk; Stefan Emeis
Institut für Meteorologie und Klimaforschung
Bereich Atmosphärische Umweltforschung (IMK-IFU)
Forschungszentrum Karlsruhe GmbH (FZK)
Garmisch-Partenkirchen
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Source: www.design-uc.nl_noordzeewi
Forschungszentrum Karlsruhe
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FINO1 research plattform
Long-running
measurements
of wind components
from 33 to 100 metres
since September 2003
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Forschungszentrum Karlsruhe
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Location of FINO1 in the North Sea
about 45 kilometres north of the island of Borkum
250-280°
210-250°
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Forschungszentrum Karlsruhe
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Mast shadow effects on wind speed measurements
(v100 / v90, Oct 2004 – Jan 2005)
1.8
v100 / v90
1.6
1.4
1.2
1.0
0.8
0
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45
90
135
180
wind direction (°)
225
270
315
360
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Wind rose
90m height, 2004
Forschungszentrum Karlsruhe
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Distribution of wind speed classes
100m height, 2004
20
18
avg: 9.8m/s
16
frequency (%)
14
12
10
8
6
4
2
0
2
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4
6
8
10
12
14
16
18
20
wind speed classes (m/s)
22
24
26
28
30
Forschungszentrum Karlsruhe
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Gradient-Richardson-Number as a measure of atmospheric
stability
∂θ
g ∂z
Ri =
T ⎛⎞∂v
⎜⎟
⎝⎠∂z
2
with
•
•
•
•
•
g = gravitational constant
T = temperature (K)
_ = potential temperature (K)
z = height (m)
v = horizontal wind speed (m/s)
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atmospheric layering
Ri
stable
>0
neutral
=0
unstable
<0
Forschungszentrum Karlsruhe
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Frequency distribution of Ri
April 2004 – July 2004, 210-250°
60
N = 2061
50.32
50
40
30
20
10
3.15
2.43
0.00
0.87
0.05
0.00
0.44
0.10
87
.1
[0
0.
>
0.
5…
0.
…
25
.1
[0
25
]
25
]
18
12
0.
5…
62
.0
[0
[-0
Ri
75
5]
]
06
0.
…
[0
[-0
.0
62
.0
-0
…
.1
25
25
0]
62
5…
5]
]
25
.1
87
.1
[-0
[-0
.2
5…
5…
-0
-0
.1
-0
87
.2
5]
5
0
<
frequency (%)
42.65
Forschungszentrum Karlsruhe
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Wind profiles depending on different Ri-classes
October 2004 – January 2005, different wind directions
250-280°
110
110
100
100
90
90
80
80
70
70
height (m)
height (m)
210-250°
60
50
60
50
40
40
30
30
all Ri classes
Ri [0…0.0625]
Ri [-0.0625…0]
Ri [-0.125…-0.0625]
Ri [-0.1875…-0.125]
Ri [-0.25…-0.1875]
Ri < -0.25
20
10
20
all Ri classes
Ri [0…0.0625]
Ri [-0.0625…0]
Ri [-0.125…-0.0625]
Ri [-0.1875…-0.125]
10
N = 4016
0
N = 1877
0
0
5
10
wind speed (m/s)
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15
20
0
5
10
wind speed (m/s)
15
Forschungszentrum Karlsruhe
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Determination of turbulence intensity
σu
t=
v
with
•
•
•
t = turbulence intensity
_u = standard deviation of horizontal wind speed (m/s)
v = mean horizontal wind speed (m/s) [based on 10 minute averages]
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Forschungszentrum Karlsruhe
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Turbulence intensity profiles depending on different Ri-classes
April 2004 – July 2004, different wind directions
250-280°
110
110
100
100
90
90
80
80
70
70
height (m)
height (m)
210-250°
60
50
60
50
40
40
30
30
20
20
10
0
0.00
all Ri classes
Ri [0.0625…0.125]
Ri [0…0.0625]
Ri [-0.0625…0]
Ri [-0.125…-0.0625]
0.05
10
N = 2034
0.10
turbulence intensity (s/v)
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0.15
0
0.00
all Ri classes
Ri [0.0625…0.125]
Ri [0…0.0625]
Ri [-0.0625…0]
Ri [-0.125…-0.0625]
0.05
N = 2397
0.10
turbulence intensity (s/v)
0.15
Forschungszentrum Karlsruhe
in der Helmholtz-Gemeinschaft
Turbulence intensity depending on wind speed (v100)
April 2004 – July 2004, 210-250°
0.50
0.45
turbulence intensity
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
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5
10
15
wind speed (m/s)
20
25
30
Forschungszentrum Karlsruhe
in der Helmholtz-Gemeinschaft
Turbulence intensity depending on wind speed (v100)
April 2004 – July 2004, 210-250°
0.50
Ri [-0.125…-0.0625]
Ri [-0.0625…0]
Ri [0…0.0625]
Ri [0.0625…0.125]
0.45
turbulence intensity
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
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5
10
15
wind speed (m/s)
20
25
30
Forschungszentrum Karlsruhe
in der Helmholtz-Gemeinschaft
Turbulence intensity depending on wave height
April 2004 – July 2004, 210-250°
0.50
Ri [-0.125…-0.0625]
Ri [-0.0625…0]
Ri [0…0.0625]
Ri [0.0625…0.125]
0.45
turbulence intensity
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
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1
2
3
wave height (m/s)
4
5
6
Forschungszentrum Karlsruhe
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Wave heigth depending on wind speed (v100)
April 2004 – July 2004, 210-250°
7
6
wave height (m)
5
4
3
2
Ri [-0.125…-0.0625]
Ri [-0.0625…0]
Ri [0…0.0625]
Ri [0.0625…0.125]
1
0
0
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5
10
15
wind speed (m/s)
20
25
30
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Forschungszentrum Karlsruhe
in der Helmholtz-Gemeinschaft
Thanks for your attention!