It is observed that a period of peak wind speeds resumes around
April to August at all sites and the lowest monthly mean wind
speed takes place in November at the end of the year. This dominant
shift may be caused by the effects of northeast-southwest
monsoons. It can be noticed that there are similar trends of
changes in the monthly mean wind speeds at all three sites during
a year. At each site, the wind is measured from a height of 65 m to
a height of 120 m. The monthly mean wind speeds increase about
15–20% of the monthly mean wind speeds at a height of 65 m.
Among three sites, site S3 has the highest monthly mean wind
speed while site S1 has the lowest monthly mean wind speed
throughout a year. Additionally, the plots of the monthly mean
wind speeds at site S3 in local wind shows a small fluctuation in
wind speed throughout a year, which can be useful for steady
power generation. Those observations can be confirmed with statistical
results in Table 3.
This wind analysis is reported by statistical values of annual
mean wind speed with corresponding variance, parameters of the
Weibull distribution that are the shape parameter and the scale
parameter, the ground surface friction coefficient, and the average
power density, at every height for all sites. The wind measurement
is treated as statistical data in determining the annual mean wind
speed and corresponding variance from Eqs. (6) and (7), respectively.
The parameters of the Weibull distribution, that is the shape
parameter and the scale parameter, are calculated from Eqs. (8)
and (9), respectively. At all sites, the annual mean wind speed
somewhat increases when the wind height increases as indicated
in Table 3. There is very good agreement between the annual mean
wind speeds and the scale parameters, which is statistically
described as the peak occurrence of the wind speed. Site S3 has
the highest annual mean wind speed with low variance.
Accordingly, the probability density functions of wind data at the
three sites at a height of 120 m are plotted as shown in Fig. 4.
It is found that site S3 has a greater frequency distribution of
higher mean wind speed than other sites where the shape parameters
are also larger as reported in Table 3. Obviously, site S3 has
strong wind conditions with the highest values of average power
densities among the three sites (68.61 W/m2 at 65 m,
75.63 W/m2 at 90 m, and 98.29 W/m2 at 120 m) even though the
ground roughness with ground surface friction coefficient of 0.17
at the sites S1 and S2 is lower than S3 due to plateau areas. It
should be noted that the shape factors for all sites in Table 3 are
more or less the same values at all three heights, although the
shape factor of site S1 at a height of 120 m is slightly higher than
the heights of 90 m and 65 m. It can be interpreted that the wind
profiles at all sites are determined by the power law equation in
Eq. (1). Therefore, the annual energy production at site S3 is
expected to be greater than others. Areas in the northeast of the
It is observed that a period of peak wind speeds resumes aroundApril to August at all sites and the lowest monthly mean windspeed takes place in November at the end of the year. This dominantshift may be caused by the effects of northeast-southwestmonsoons. It can be noticed that there are similar trends ofchanges in the monthly mean wind speeds at all three sites duringa year. At each site, the wind is measured from a height of 65 m toa height of 120 m. The monthly mean wind speeds increase about15–20% of the monthly mean wind speeds at a height of 65 m.Among three sites, site S3 has the highest monthly mean windspeed while site S1 has the lowest monthly mean wind speedthroughout a year. Additionally, the plots of the monthly meanwind speeds at site S3 in local wind shows a small fluctuation inwind speed throughout a year, which can be useful for steadypower generation. Those observations can be confirmed with statisticalresults in Table 3.This wind analysis is reported by statistical values of annualmean wind speed with corresponding variance, parameters of theWeibull distribution that are the shape parameter and the scaleparameter, the ground surface friction coefficient, and the averagepower density, at every height for all sites. The wind measurementis treated as statistical data in determining the annual mean windspeed and corresponding variance from Eqs. (6) and (7), respectively.The parameters of the Weibull distribution, that is the shapeparameter and the scale parameter, are calculated from Eqs. (8)and (9), respectively. At all sites, the annual mean wind speedsomewhat increases when the wind height increases as indicatedin Table 3. There is very good agreement between the annual meanwind speeds and the scale parameters, which is statisticallydescribed as the peak occurrence of the wind speed. Site S3 hasthe highest annual mean wind speed with low variance.Accordingly, the probability density functions of wind data at thethree sites at a height of 120 m are plotted as shown in Fig. 4.It is found that site S3 has a greater frequency distribution ofhigher mean wind speed than other sites where the shape parametersare also larger as reported in Table 3. Obviously, site S3 hasstrong wind conditions with the highest values of average powerdensities among the three sites (68.61 W/m2 at 65 m,75.63 W/m2 at 90 m, and 98.29 W/m2 at 120 m) even though theground roughness with ground surface friction coefficient of 0.17at the sites S1 and S2 is lower than S3 due to plateau areas. Itshould be noted that the shape factors for all sites in Table 3 aremore or less the same values at all three heights, although theshape factor of site S1 at a height of 120 m is slightly higher thanthe heights of 90 m and 65 m. It can be interpreted that the windprofiles at all sites are determined by the power law equation inEq. (1) ดังนั้น การผลิตพลังงานประจำที่ S3 เป็นคาดว่าจะมากกว่าคนอื่น ในประเทศ
การแปล กรุณารอสักครู่..