On the Wind Profile above Plant Canopies and its Aerodynamic Properties

Kotoda, Kazuo; Hayashi, Yoshihiko

doi:10.2480/agrmet.35.221

Cited by 5 publications

(7 citation statements)

References 12 publications

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“…Little research, however, has been conducted in the past concerning the relation between d and zo. Takeda (1966), Kondo (1971Kondo ( , 1972, Maki (1975 a, b), and Kotoda and Hayashi (1980) expressed the relation between d and zo by assuming the continuity of some parameter within and above the canopy. These studies fall into the following two categories in which two different theories are applied.…”

Section: Interrelation Of D and Zomentioning

confidence: 99%

“…These studies fall into the following two categories in which two different theories are applied. Takeda (1966), Maki (1975 a, b), and Kotoda and Hayashi (1980) determined an empirical eddy viscosity within the canopy, describing the relation between d and zo by assuming the continuity of eddy viscosity within and above the canopy.…”

Section: Interrelation Of D and Zomentioning

confidence: 99%

“…(12) or (13), regardless of the canopy density. Kotoda and Hayashi (1980) expressed the eddy viscosity within the canopy as where B and m are the empirical constants. The value of B and m can be determined by the observation of wind speed profile over the vegetated surface.…”

Section: K=ahumentioning

confidence: 99%

“…3and 14into Eq. (4), expressed as Kotoda and Hayashi (1980) indicated that the relationships among the d, z0, and h could be expressed by Eq. (15) if the empirical constants B and m are determined in advance, regardless of the canopy height and canopy density.…”

Section: K=ahumentioning

confidence: 99%

“…This stage can be separated into two arguments. One argument assumes that either z0 or d does not depend on wind speed (Chamberlain (1968), Oliver (1971), Munro and Oke (1973) ), while the other assumes that wind speed and friction velocity influence both z° and d (Tani (1960), Penman and Long (1960), Takeda (1965), Udagawa (1966), Maki et al (1968), Kotoda (1979), Hayashi (1979), Kotoda and Hayashi (1980), Hayashi and Kotoda (1980), Azevedo and Verma (1986)).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Relationships between the Zero-plane Displacement and the Roughness Length over Sorghum and Alfalfa Canopies.

Kimura

Otsuki

Kamichika

1999

J. Agric. Meteorol.

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The effect of wind speed on the aerodynamical parameters, namely the zero-plane displacement d and roughness length z°, and the relationships between d and z° is discussed. Experiments conducted in sorghum and alfalfa fields reveal that d decreases and z° increases with increasing wind speed or friction velocity. The relations between d and z° obtained in these experiments are not well expressed by previous equations that were presented during the last several decades. Thus, new equations representing the relationships between d and z°, and a newly designed concept for eddy viscosity within the canopy are proposed and experimentally tested in sorghum, alfalfa, and tanukimame fields. The test results demonstrate that calculations from present equations coincide with the observed results. In the tanukimame field, however, the zero-plane displacement and roughness length do not vary with wind speed when the leaf area index LAI is large (LAI=5.6). On this point, it is considered that the dependence of the zero-plane displacement and roughness length on wind speed are influenced by the leaf area index and the drag coefficient for an individual leaf.

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