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 C Slack

Research output: Contribution to journalArticle

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.

Original languageUndefined/Unknown
Pages (from-to)673-681
Number of pages9
JournalPesquisa Agropecuaria Brasileira
Volume31
Issue number10
StatePublished - Oct 1996

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surface roughness
aerodynamics
Cynodon
wind speed
Cynodon dactylon
Hot Temperature
heat
momentum
data analysis
methodology

Keywords

  • Friction velocity
  • Momentum
  • Rough Reynolds number
  • Roughness length
  • Sensible heat

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)

Cite this

Resistência aerodinâmica : Efeito dos métodos usados para especificar os parâmetros de rugosidade da superfície vegetada. / Guerra, Antonio Fernando; Slack, Donald C.

In: Pesquisa Agropecuaria Brasileira, Vol. 31, No. 10, 10.1996, p. 673-681.

Research output: Contribution to journalArticle

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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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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.

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KW - Sensible heat

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