Resistência aerodinâmica: Efeito dos métodos usados para especificar os parâmetros de rugosidade da superfície vegetada

Antonio Fernando Guerra; Donald Carl Slack

Resistência aerodinâmica: Efeito dos métodos usados para especificar os parâmetros de rugosidade da superfície vegetada

Translated title of the contribution: Aerodynamic resistance: Effect of the methods used to specify the vegetated surface roughness parameters

Antonio Fernando Guerra, Donald Carl Slack

Agriculture and Biosystems Engineering

Research output: Contribution to journal › Article › peer-review

Abstract

The purposes of this study were to determine the surface roughness parameters for momentum (z_0m) and heat (z_0h) for bermudagrass and to examine the effect of using different criteria for selecting these surface roughness parameters on the calculation of the aerodynamic resistances. Analysis of the data collected over bermudagrass suggests that z_0m, is virtually constant at wind speeds greater than 2 m/s, but increases rapidly as wind speeds decrease below 2 m/s. For wind speeds larger than 2 m/s it resulted in an average z_0m of 0.0006 m and an average z_0h of 0.00015 m, which is about 1/7.6 of z_0m. The use of the different criteria to specify the surface roughness parameters resulted in considerable differences in the calculation of the aerodynamic resistances.

Translated title of the contribution	Aerodynamic resistance: Effect of the methods used to specify the vegetated surface roughness parameters
Original language	Portuguese
Pages (from-to)	673-681
Number of pages	9
Journal	Pesquisa Agropecuaria Brasileira
Volume	31
Issue number	10
State	Published - Oct 1996

Keywords

Friction velocity
Momentum
Rough Reynolds number
Roughness length
Sensible heat

ASJC Scopus subject areas

Animal Science and Zoology
Agronomy and Crop Science

Cite this

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title = "Resist{\^e}ncia aerodin{\^a}mica: Efeito dos m{\'e}todos usados para especificar os par{\^a}metros de rugosidade da superf{\'i}cie vegetada",

abstract = "The purposes of this study were to determine the surface roughness parameters for momentum (z0m) and heat (z0h) for bermudagrass and to examine the effect of using different criteria for selecting these surface roughness parameters on the calculation of the aerodynamic resistances. Analysis of the data collected over bermudagrass suggests that z0m, is virtually constant at wind speeds greater than 2 m/s, but increases rapidly as wind speeds decrease below 2 m/s. For wind speeds larger than 2 m/s it resulted in an average z0m of 0.0006 m and an average z0h of 0.00015 m, which is about 1/7.6 of z0m. The use of the different criteria to specify the surface roughness parameters resulted in considerable differences in the calculation of the aerodynamic resistances.",

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T2 - Efeito dos métodos usados para especificar os parâmetros de rugosidade da superfície vegetada

AU - Guerra, Antonio Fernando

AU - Slack, Donald Carl

PY - 1996/10

Y1 - 1996/10

N2 - The purposes of this study were to determine the surface roughness parameters for momentum (z0m) and heat (z0h) for bermudagrass and to examine the effect of using different criteria for selecting these surface roughness parameters on the calculation of the aerodynamic resistances. Analysis of the data collected over bermudagrass suggests that z0m, is virtually constant at wind speeds greater than 2 m/s, but increases rapidly as wind speeds decrease below 2 m/s. For wind speeds larger than 2 m/s it resulted in an average z0m of 0.0006 m and an average z0h of 0.00015 m, which is about 1/7.6 of z0m. The use of the different criteria to specify the surface roughness parameters resulted in considerable differences in the calculation of the aerodynamic resistances.

AB - The purposes of this study were to determine the surface roughness parameters for momentum (z0m) and heat (z0h) for bermudagrass and to examine the effect of using different criteria for selecting these surface roughness parameters on the calculation of the aerodynamic resistances. Analysis of the data collected over bermudagrass suggests that z0m, is virtually constant at wind speeds greater than 2 m/s, but increases rapidly as wind speeds decrease below 2 m/s. For wind speeds larger than 2 m/s it resulted in an average z0m of 0.0006 m and an average z0h of 0.00015 m, which is about 1/7.6 of z0m. The use of the different criteria to specify the surface roughness parameters resulted in considerable differences in the calculation of the aerodynamic resistances.

KW - Friction velocity

KW - Momentum

KW - Rough Reynolds number

KW - Roughness length

KW - Sensible heat

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Resistência aerodinâmica: Efeito dos métodos usados para especificar os parâmetros de rugosidade da superfície vegetada

Abstract

Keywords

ASJC Scopus subject areas

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