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Analytical and Numerical Study of Thermally Stratified Flow above a forest

Hultmark, Ellinor LU (2015) MVK920 20151
Department of Energy Sciences
Abstract
In order for our energy consumption to be sustainable, we need to rely more and more on renewable energy
resources, such as solar power and wind power. In Sweden, 69% of the land area is covered in forest. To open
up the possibility of exploiting these forested areas for wind power production, it is desired to gain a better
knowledge of the flow situation above forests.
An analytical and a numerical study has been carried out, in order to investigate the flow above forests.
The thermal stratification of the atmospheric boundary layer has been taken into account to investigate its
influence on the characteristics of the flow. The analytical study was performed by analyzing meteorological
measurements collected by Göteborg Energi at a... (More)
In order for our energy consumption to be sustainable, we need to rely more and more on renewable energy
resources, such as solar power and wind power. In Sweden, 69% of the land area is covered in forest. To open
up the possibility of exploiting these forested areas for wind power production, it is desired to gain a better
knowledge of the flow situation above forests.
An analytical and a numerical study has been carried out, in order to investigate the flow above forests.
The thermal stratification of the atmospheric boundary layer has been taken into account to investigate its
influence on the characteristics of the flow. The analytical study was performed by analyzing meteorological
measurements collected by Göteborg Energi at a site near Töreboda, Sweden, which is mostly covered in forest.
In the numerical study, Large Eddy Simulations were carried out. The results obtained from the numerical
study were compared to the results of the analytical study.
The results showed that the characteristics of the flow varies with thermal stratifiaction. The wind shear
was highest with stable stratification, while the turbulence intensity was highest with unstable stratification.
The results from the Large Eddy Simulations showed some agreement with the results from the analytical
study, but further improvements are needed for better agreement. When investigating the effect of the flow,
the results showed that the forest increased both the wind shear and the turbulence intensity. At the site in
Töreboda, there were high occurrence of non-favourable wind conditions for wind power, with high wind shear
and high turbulence intensity. (Less)
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author
Hultmark, Ellinor LU
supervisor
organization
course
MVK920 20151
year
type
H2 - Master's Degree (Two Years)
subject
keywords
forest, thermal stratification, large-eddy simulation, LES, Richardson number, atmospheric boundary layer, wind power
report number
ISRN LUTMDN/TMHP-15/5354-SE
ISSN
0282-1990
language
English
id
7374046
date added to LUP
2015-06-22 10:17:53
date last changed
2015-06-22 10:17:53
@misc{7374046,
  abstract     = {In order for our energy consumption to be sustainable, we need to rely more and more on renewable energy
resources, such as solar power and wind power. In Sweden, 69% of the land area is covered in forest. To open
up the possibility of exploiting these forested areas for wind power production, it is desired to gain a better
knowledge of the flow situation above forests.
An analytical and a numerical study has been carried out, in order to investigate the flow above forests.
The thermal stratification of the atmospheric boundary layer has been taken into account to investigate its
influence on the characteristics of the flow. The analytical study was performed by analyzing meteorological
measurements collected by Göteborg Energi at a site near Töreboda, Sweden, which is mostly covered in forest.
In the numerical study, Large Eddy Simulations were carried out. The results obtained from the numerical
study were compared to the results of the analytical study.
The results showed that the characteristics of the flow varies with thermal stratifiaction. The wind shear
was highest with stable stratification, while the turbulence intensity was highest with unstable stratification.
The results from the Large Eddy Simulations showed some agreement with the results from the analytical
study, but further improvements are needed for better agreement. When investigating the effect of the flow,
the results showed that the forest increased both the wind shear and the turbulence intensity. At the site in
Töreboda, there were high occurrence of non-favourable wind conditions for wind power, with high wind shear
and high turbulence intensity.},
  author       = {Hultmark, Ellinor},
  issn         = {0282-1990},
  keyword      = {forest,thermal stratification,large-eddy simulation,LES,Richardson number,atmospheric boundary layer,wind power},
  language     = {eng},
  note         = {Student Paper},
  title        = {Analytical and Numerical Study of Thermally Stratified Flow above a forest},
  year         = {2015},
}