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Turbulent air flow in forest stands: a wind tunnel study Warland, Jon S.
Abstract
This study used a wind tunnel to examine turbulent flow in thinned forests and downwind of shelterbelts. High frequency measurements of the wind components were made using a Dantec triaxial hot-wire probe. Four thinning treatments were studied, consisting of uniformly spaced model trees with plant area index (PAT) = 4.5, 1.7, 0.7 and 0.4. Turbulence statistics up to the fourth order, as well as results from quadrant analysis and spectral densities, were compared to a similar field study, showing good agreement between model and field results. Length and time scales associated with the canopy turbulence were described with linear stability theory. Forest thinning was shown to increase turbulent energy and momentum transport within the canopy. Four shelterbelt widths were studied in both laminar and turbulent flows. Profiles were measured at both upstream and downstream positions, and without shelterbelts present. Turbulence statistics up to the fourth order, spectral densities and results from quadrant analysis were examined. The turbulent flow cases showed little variation with width due to mixing of the flow by turbulence, while the laminar flow cases showed strong differences between widths extending much further downwind.
Item Metadata
Title |
Turbulent air flow in forest stands: a wind tunnel study
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1996
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Description |
This study used a wind tunnel to examine turbulent flow in thinned forests and
downwind of shelterbelts. High frequency measurements of the wind components were
made using a Dantec triaxial hot-wire probe. Four thinning treatments were studied, consisting
of uniformly spaced model trees with plant area index (PAT) = 4.5, 1.7, 0.7 and 0.4.
Turbulence statistics up to the fourth order, as well as results from quadrant analysis and
spectral densities, were compared to a similar field study, showing good agreement between
model and field results. Length and time scales associated with the canopy turbulence
were described with linear stability theory. Forest thinning was shown to increase
turbulent energy and momentum transport within the canopy. Four shelterbelt widths
were studied in both laminar and turbulent flows. Profiles were measured at both upstream
and downstream positions, and without shelterbelts present. Turbulence statistics
up to the fourth order, spectral densities and results from quadrant analysis were examined.
The turbulent flow cases showed little variation with width due to mixing of the
flow by turbulence, while the laminar flow cases showed strong differences between
widths extending much further downwind.
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Extent |
3806967 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-02-17
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0099048
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1996-11
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.