落葉した森林内における乱流拡散係数及び渦構造の計測(渦・回転+大気(3),一般講演)

概要

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In order to investigate turbulent diffusion and eddy structure in defoliate forest, several times of wind measurements were conducted several times in a period of three weeks, from late December to early January of 2009, using an observation tower of 20m in height, located in the campus of Kanazawa University. Five ultra-sonic anemometers are installed on the tower, and the average wind velocities and temperatures, as well as their fluctuations are monitored at five different heights simultaneously. Vertical profiles of average wind velocities are found approximately an exponential profile. It is also found that the eddy diffusivities take generally greater values as the wind speeds are large. Anisotropy of eddy diffusivities between the vertical and horizontal directions is also observed, where the horizontal eddy diffusivities are roughly two times larger than the vertical ones. The anisotropy is particularly pronounced when the trees lost their leaves completely in a period of late December to early January.
日本流体力学会の論文
2009-09-02