Universität zu Köln

Zhang, Jie ORCID: 0000-0003-1379-5976, Li, Guang, Shi, Li, Huang, Ning and Shao, Yaping ORCID: 0000-0002-2041-5479 (2022). Impact of turbulence on aeolian particle entrainment: results from wind-tunnel experiments. Atmos. Chem. Phys., 22 (14). S. 9525 - 9536. GOTTINGEN: COPERNICUS GESELLSCHAFT MBH. ISSN 1680-7324

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Abstract

We hypothesize that large eddies play a major role in the entrainment of aeolian particles. To test this, wind-tunnel experiments are carried out to measure the particle entrainment rate for various sizes and flow conditions. Wind-tunnel flows are usually neutrally stratified with no large eddies, which are typically seen in convective atmospheric boundary layers. Here, a novel technique is applied, by deploying a piece of randomly fluttering cloth, to generate large eddies similar to convective eddies, here referred to as quasi-convective turbulence. The characteristics of quasi-convective turbulence are analyzed with respect to neutral turbulence in the Monin-Obukhov similarity framework, and the probability distributions of surface shear stress are examined. We show that for a given mean flow speed and in comparison with neutral flow conditions, quasi-convective turbulence increases the surface shear stress and alters its probability distribution and hence substantially enhances the entrainment of sand and dust particles. Our hypothesis is thus confirmed by the wind-tunnel experiments. We also explain why large eddies are important to aeolian entrainment and transport.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Zhang, Jie UNSPECIFIED orcid.org/0000-0003-1379-5976 UNSPECIFIED Li, Guang UNSPECIFIED UNSPECIFIED UNSPECIFIED Shi, Li UNSPECIFIED UNSPECIFIED UNSPECIFIED Huang, Ning UNSPECIFIED UNSPECIFIED UNSPECIFIED Shao, Yaping UNSPECIFIED orcid.org/0000-0002-2041-5479 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-674777
DOI:	10.5194/acp-22-9525-2022
Journal or Publication Title:	Atmos. Chem. Phys.
Volume:	22
Number:	14
Page Range:	S. 9525 - 9536
Date:	2022
Publisher:	COPERNICUS GESELLSCHAFT MBH
Place of Publication:	GOTTINGEN
ISSN:	1680-7324
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language FRICTION VELOCITY; DUST EMISSION; SALTATION; ROUGHNESS; SIMULATION; PARAMETERIZATION; FLUXES; URBAN Multiple languages Environmental Sciences; Meteorology & Atmospheric Sciences Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/67477