Page 171 - Fluid Power Engineering

144 Chapter Seven

Sample Statistics: Mean speed-up (site-reference) [m/s]
24
4.5
3.1
22 -1.2
1.7
Wind speed at reference position [m/s] 16 8 -5.4
0.3
20
-2.6
18
-4
-6.9
-8.3
14
12
10

2 6 4
0
20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360
Wind direction at reference position [deg]
(a)

Polynomial model of sample statistics: Mean of wind speed-up [m/s]
24
3.5
2.6
22 -0.1
1.7
Wind speed at reference position [m/s] 16 8 -2.7
0.8
20
-1
18
-1.9
-3.6
-4.5
14
12
10

2 6 4
0
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360
Wind direction at reference position [deg]
(b)

FIGURE 7-14 The shades in the plots are wind speed-up in a cell of the
matrix. A cell is 1 direction by 1 m/s wind speed. Plot of concurrent data
◦
series is in (a) with some empty cells. Linear regression is used to fill up the
empty cells and smooth the variation, as shown in (b).