行政院國家科學委員會專題研究計畫成果報告:防風設施防風效果及環境風場之數值與實驗研究﹝2/2﹞
Date Issued
2003
Date
2003
Author(s)
DOI
912313B002317
Abstract
The study is a NSC two-year project
(2001-2003) entitled “Numerical and
experimental investigations on shelter
effectiveness and wind flow near windbreaks”.
The main objective of this study is to
numerically as well as experimentally
investigate the shelter effectiveness and wind
flows near windbreaks. A combination of
numerical scenario simulations and wind tunnel
experiments of windbreak flows, considering
the effects of the geometric shape, porosity of
horizontal profile, porosity of vertical profile,
meteorological conditions, and surrounding
terrain on shelter effectiveness, has been
conducted. In the first year, a two-dimensional
dynamic windbreak model is developed. The
Large Eddy Simulation (LES) is selected as the
turbulence model in the study, which is
incorporated in the governing equations:
Navier-Stokes equations. A series of numerical
scenario simulations of windbreak flows are
conducted so that the effects of the geometric
shape, porosity of horizontal profile, porosity of
vertical profile, meteorological conditions, and
surrounding terrain on shelter effectiveness can
be obtained. To simulate windbreak flows more
accurately, the boundary-fitted coordinate is
employed in the study to fit the irregular
greenhouse boundary by transforming the
complex physical domain onto the simple
numerical domain. The up-winding finite
difference method with explicit scheme is used
to solve the Navier-Stokes equations. In the
second year, an experimental procedure for a
medium size boundary layer wind tunnel is also
carried out. The wind tunnel results are used to
demonstrate the mechanism of wind reduction
of windbreaks and to verify the first-year
numerical results.
The report demonstrates the results of this
two-year project. The results include CFD
numerical model establishment, model
verification with reliable measured data, setup
pf wind tunnel experiments, and the effects of
the geometric shape, porosity of horizontal
profile, porosity of vertical profile,
meteorological conditions, and surrounding
terrain on shelter effectiveness. The 40%
porosity shelter gives the most effective wind
reduction effect. The results of the numerical
scenario simulations and wind tunnel
experiments can provide the essential
information of the best-designed windbreaks
from the viewpoint of ecology.
Subjects
Windbreaks
Shelter Efficiency
Wind Flows
Computational Fluid Dynamics
Wind Tunnel Experiment
Publisher
臺北市：國立臺灣大學生物環境系統工程學系暨研究所
Type
report
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