Reach-averaged flow resistance in gravel-bed streams

Previous studies about flow resistance in gravel-bed streams mostly use the log-law form and establish the relationship between the friction factor and the relative flow depth based on field data. However, most established relations do not perform very well when applied to shallow water zones with r...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Liguo Zhang, Wenguang Luo
Formato:	article
Lenguaje:	EN
Publicado:	IWA Publishing 2021
Materias:	einstein flow parameter form drag gravel-bed streams reach-averaged Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350
Acceso en línea:	https://doaj.org/article/b1fba8e83f284d2ea13d523ce4f232b7
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:b1fba8e83f284d2ea13d523ce4f232b7
record_format	dspace
spelling	oai:doaj.org-article:b1fba8e83f284d2ea13d523ce4f232b72021-11-05T19:01:37ZReach-averaged flow resistance in gravel-bed streams2040-22442408-935410.2166/wcc.2020.053https://doaj.org/article/b1fba8e83f284d2ea13d523ce4f232b72021-08-01T00:00:00Zhttp://jwcc.iwaponline.com/content/12/5/1580https://doaj.org/toc/2040-2244https://doaj.org/toc/2408-9354Previous studies about flow resistance in gravel-bed streams mostly use the log-law form and establish the relationship between the friction factor and the relative flow depth based on field data. However, most established relations do not perform very well when applied to shallow water zones with relatively large roughness. In order to clarify the hydraulic variables defined in the single cross-section, and find the reasons that reflect the instability of flow and uneven boundaries of the river, the concepts of hydraulic variables, such as hydraulic radius, are re-defined in the river reach in the paper. The form drag in the river reach is solved based on a reach-averaged flow resistance model which is developed by force balance analyzing of the water body in the given river reach. The reach-averaged form drag relation is then formulated by incorporating the Einstein flow parameter and a newly derived roughness parameter defined in the river reach. A large number of field data (12 datasets, 780 field measurements) is applied to calibrate and validate the form drag relation. The relation is found to give better agreement with the field data in predicting flow velocity in comparison with existing flow resistance equations. A unique feature of the reach-averaged resistance relation is that it can apply to both deep and shallow water zones, which can be treated as a bridge to link the flow hydraulics in plain rivers and mountain streams. HIGHLIGHTS For river sections, the variables of each river section are defined first. Skin resistance is solvable (refer to the relevant literature, its formation mechanism, etc.), so the solution obtains the morphological resistance value.; Probing morphological resistance influence factors.; With the new method, we have improved the calculation accuracy of the surface resistance of complex riverbeds.;Liguo ZhangWenguang LuoIWA Publishingarticleeinstein flow parameterform draggravel-bed streamsreach-averagedEnvironmental technology. Sanitary engineeringTD1-1066Environmental sciencesGE1-350ENJournal of Water and Climate Change, Vol 12, Iss 5, Pp 1580-1597 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	einstein flow parameter form drag gravel-bed streams reach-averaged Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350
spellingShingle	einstein flow parameter form drag gravel-bed streams reach-averaged Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Liguo Zhang Wenguang Luo Reach-averaged flow resistance in gravel-bed streams
description	Previous studies about flow resistance in gravel-bed streams mostly use the log-law form and establish the relationship between the friction factor and the relative flow depth based on field data. However, most established relations do not perform very well when applied to shallow water zones with relatively large roughness. In order to clarify the hydraulic variables defined in the single cross-section, and find the reasons that reflect the instability of flow and uneven boundaries of the river, the concepts of hydraulic variables, such as hydraulic radius, are re-defined in the river reach in the paper. The form drag in the river reach is solved based on a reach-averaged flow resistance model which is developed by force balance analyzing of the water body in the given river reach. The reach-averaged form drag relation is then formulated by incorporating the Einstein flow parameter and a newly derived roughness parameter defined in the river reach. A large number of field data (12 datasets, 780 field measurements) is applied to calibrate and validate the form drag relation. The relation is found to give better agreement with the field data in predicting flow velocity in comparison with existing flow resistance equations. A unique feature of the reach-averaged resistance relation is that it can apply to both deep and shallow water zones, which can be treated as a bridge to link the flow hydraulics in plain rivers and mountain streams. HIGHLIGHTS For river sections, the variables of each river section are defined first. Skin resistance is solvable (refer to the relevant literature, its formation mechanism, etc.), so the solution obtains the morphological resistance value.; Probing morphological resistance influence factors.; With the new method, we have improved the calculation accuracy of the surface resistance of complex riverbeds.;
format	article
author	Liguo Zhang Wenguang Luo
author_facet	Liguo Zhang Wenguang Luo
author_sort	Liguo Zhang
title	Reach-averaged flow resistance in gravel-bed streams
title_short	Reach-averaged flow resistance in gravel-bed streams
title_full	Reach-averaged flow resistance in gravel-bed streams
title_fullStr	Reach-averaged flow resistance in gravel-bed streams
title_full_unstemmed	Reach-averaged flow resistance in gravel-bed streams
title_sort	reach-averaged flow resistance in gravel-bed streams
publisher	IWA Publishing
publishDate	2021
url	https://doaj.org/article/b1fba8e83f284d2ea13d523ce4f232b7
work_keys_str_mv	AT liguozhang reachaveragedflowresistanceingravelbedstreams AT wenguangluo reachaveragedflowresistanceingravelbedstreams
_version_	1718444059788312576

Reach-averaged flow resistance in gravel-bed streams

Ejemplares similares