Aerodynamic Characteristics Over Fine-Grained Gravel Surfaces in a Wind Tunnel

Gravels can protect soil from wind erosion, however, there is little known about the effects of fine-grained gravel on aerodynamic characteristics of the near-surface airflow. Drag coefficient, wind-speed gradient, and turbulent transfer coefficient over different coverages of gravel surfaces were i...

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Autores principales:	Jiaqi Liu, Reiji Kimura, Jing Wu
Formato:	article
Lenguaje:	EN
Publicado:	Frontiers Media S.A. 2021
Materias:	arid regions drag coefficient gravel coverage turbulent transfer coefficient wind-speed gradient Science Q
Acceso en línea:	https://doaj.org/article/eafd6c5b384441788afb437ac00c995f
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id	oai:doaj.org-article:eafd6c5b384441788afb437ac00c995f
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spelling	oai:doaj.org-article:eafd6c5b384441788afb437ac00c995f2021-11-30T14:24:43ZAerodynamic Characteristics Over Fine-Grained Gravel Surfaces in a Wind Tunnel2296-646310.3389/feart.2021.758910https://doaj.org/article/eafd6c5b384441788afb437ac00c995f2021-11-01T00:00:00Zhttps://www.frontiersin.org/articles/10.3389/feart.2021.758910/fullhttps://doaj.org/toc/2296-6463Gravels can protect soil from wind erosion, however, there is little known about the effects of fine-grained gravel on aerodynamic characteristics of the near-surface airflow. Drag coefficient, wind-speed gradient, and turbulent transfer coefficient over different coverages of gravel surfaces were investigated in a compact boundary-layer wind tunnel. The drag coefficient of the fine-grained gravel surface reached the maximum value at 15% coverage and then tended to stabilize at gravel coverage 20% and greater. At a height of 4 cm, near-surface airflow on gravel surfaces can be divided clearly into upper and lower sublayers, defined as the inertial and roughness sublayers, respectively. The coefficient of variation of wind speed over gravel surfaces in the roughness sublayer was 8.6 times that in the inertial sublayer, indicating a greater effect of gravel coverage on wind-speed fluctuations in the lower layer. At a height of 4 cm, wind-speed fluctuations under the observed wind speeds were independent of changes in gravel coverage. In addition, an energy-exchange region, where sand particles can absorb more energy from the surrounding airflow, was found between the roughness and inertial sublayers, enhancing the erosional state of wind-blown sand. This finding can be applied to evaluate the aerodynamic stability of the gravel surface in the Gobi Desert and provide a theoretical basis for elucidation of the vertical distributions of wind-blown sand flux.Jiaqi LiuReiji KimuraJing WuFrontiers Media S.A.articlearid regionsdrag coefficientgravel coverageturbulent transfer coefficientwind-speed gradientScienceQENFrontiers in Earth Science, Vol 9 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	arid regions drag coefficient gravel coverage turbulent transfer coefficient wind-speed gradient Science Q
spellingShingle	arid regions drag coefficient gravel coverage turbulent transfer coefficient wind-speed gradient Science Q Jiaqi Liu Reiji Kimura Jing Wu Aerodynamic Characteristics Over Fine-Grained Gravel Surfaces in a Wind Tunnel
description	Gravels can protect soil from wind erosion, however, there is little known about the effects of fine-grained gravel on aerodynamic characteristics of the near-surface airflow. Drag coefficient, wind-speed gradient, and turbulent transfer coefficient over different coverages of gravel surfaces were investigated in a compact boundary-layer wind tunnel. The drag coefficient of the fine-grained gravel surface reached the maximum value at 15% coverage and then tended to stabilize at gravel coverage 20% and greater. At a height of 4 cm, near-surface airflow on gravel surfaces can be divided clearly into upper and lower sublayers, defined as the inertial and roughness sublayers, respectively. The coefficient of variation of wind speed over gravel surfaces in the roughness sublayer was 8.6 times that in the inertial sublayer, indicating a greater effect of gravel coverage on wind-speed fluctuations in the lower layer. At a height of 4 cm, wind-speed fluctuations under the observed wind speeds were independent of changes in gravel coverage. In addition, an energy-exchange region, where sand particles can absorb more energy from the surrounding airflow, was found between the roughness and inertial sublayers, enhancing the erosional state of wind-blown sand. This finding can be applied to evaluate the aerodynamic stability of the gravel surface in the Gobi Desert and provide a theoretical basis for elucidation of the vertical distributions of wind-blown sand flux.
format	article
author	Jiaqi Liu Reiji Kimura Jing Wu
author_facet	Jiaqi Liu Reiji Kimura Jing Wu
author_sort	Jiaqi Liu
title	Aerodynamic Characteristics Over Fine-Grained Gravel Surfaces in a Wind Tunnel
title_short	Aerodynamic Characteristics Over Fine-Grained Gravel Surfaces in a Wind Tunnel
title_full	Aerodynamic Characteristics Over Fine-Grained Gravel Surfaces in a Wind Tunnel
title_fullStr	Aerodynamic Characteristics Over Fine-Grained Gravel Surfaces in a Wind Tunnel
title_full_unstemmed	Aerodynamic Characteristics Over Fine-Grained Gravel Surfaces in a Wind Tunnel
title_sort	aerodynamic characteristics over fine-grained gravel surfaces in a wind tunnel
publisher	Frontiers Media S.A.
publishDate	2021
url	https://doaj.org/article/eafd6c5b384441788afb437ac00c995f
work_keys_str_mv	AT jiaqiliu aerodynamiccharacteristicsoverfinegrainedgravelsurfacesinawindtunnel AT reijikimura aerodynamiccharacteristicsoverfinegrainedgravelsurfacesinawindtunnel AT jingwu aerodynamiccharacteristicsoverfinegrainedgravelsurfacesinawindtunnel
_version_	1718406537381150720

Aerodynamic Characteristics Over Fine-Grained Gravel Surfaces in a Wind Tunnel

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