| Summary: | 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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