A depth-averaged two-phase model for debris flows over erodible beds

Li, Ji; Cao, Zhixian; Hu, Kaiheng; Pender, Gareth; Liu, Qingquan

doi:10.1002/esp.4283

Journal article 827 views

A depth-averaged two-phase model for debris flows over erodible beds

Ji Li

, Zhixian Cao, Kaiheng Hu, Gareth Pender, Qingquan Liu

Earth Surface Processes and Landforms, Volume: 43, Issue: 4, Pages: 817 - 839

Swansea University Author: Ji Li

Full text not available from this repository: check for access using links below.

Check full text

DOI (Published version): 10.1002/esp.4283

Abstract

Mass exchange between debris flow and the bed plays a vital role in debris flow dynamics. Here a depth-averaged two-phase model is proposed for debris flows over erodible beds. Compared to previous depth-averaged two-phase models, the present model features a physical step forward by explicitly inco...

Full description

Published in:	Earth Surface Processes and Landforms
ISSN:	0197-9337
Published:	2018
Online Access:	Check full text
URI:	https://cronfa.swan.ac.uk/Record/cronfa51802
Tags:	Add Tag No Tags, Be the first to tag this record!

first_indexed	2019-09-12T14:49:04Z
last_indexed	2020-12-18T04:13:23Z
id	cronfa51802
recordtype	SURis
fullrecord	<?xml version="1.0"?><rfc1807><datestamp>2020-12-17T10:40:31.1165861</datestamp><bib-version>v2</bib-version><id>51802</id><entry>2019-09-12</entry><title>A depth-averaged two-phase model for debris flows over erodible beds</title><swanseaauthors><author><sid>4123c4ddbcd6e77f580974c661461c7c</sid><ORCID>0000-0003-4328-3197</ORCID><firstname>Ji</firstname><surname>Li</surname><name>Ji Li</name><active>true</active><ethesisStudent>false</ethesisStudent></author></swanseaauthors><date>2019-09-12</date><deptcode>CIVL</deptcode><abstract>Mass exchange between debris flow and the bed plays a vital role in debris flow dynamics. Here a depth-averaged two-phase model is proposed for debris flows over erodible beds. Compared to previous depth-averaged two-phase models, the present model features a physical step forward by explicitly incorporating the mass exchange between the flow and the bed. A widely used closure model in fluvial hydraulics is employed to estimate the mass exchange between the debris flow and the bed, and an existing relationship for bed entrainment rate is introduced for comparison. Also, two distinct closure models for the bed shear stresses are evaluated. One uses the Coulomb friction law and Manning’s equation to determine the solid and fluid resistances respectively, while the other employs an analytically derived formula for the solid phase and the mixing length approach for the fluid phase. A well-balanced numerical algorithm is applied to solve the governing equations of the model. The present model is first shown to reproduce average sediment concentrations in steady and uniform debris flows over saturated bed as compared to an existing formula underpinned by experimental datasets. Then, it is demonstrated to perform rather well as compared to the full set of USGS large-scale experimental debris flows over erodible beds, in producing debris flow depth, front location and bed deformation. The effects of initial conditions on debris flow mass and momentum gain are resolved by the present model, which explicitly demonstrates the roles of the wetness, porosity and volume of bed sediments in affecting the flow. By virtue of extended modeling cases, the present model produces debris flow efficiency that, as revealed by existing observations and empirical relations, increases with initial volume, which is enhanced by mass gain from the bed.</abstract><type>Journal Article</type><journal>Earth Surface Processes and Landforms</journal><volume>43</volume><journalNumber>4</journalNumber><paginationStart>817</paginationStart><paginationEnd>839</paginationEnd><publisher/><placeOfPublication/><isbnPrint/><isbnElectronic/><issnPrint>0197-9337</issnPrint><issnElectronic/><keywords>debris flow; erodible bed; mass exchange; two-phase model; debris flow efficiency</keywords><publishedDay>30</publishedDay><publishedMonth>3</publishedMonth><publishedYear>2018</publishedYear><publishedDate>2018-03-30</publishedDate><doi>10.1002/esp.4283</doi><url/><notes/><college>COLLEGE NANME</college><department>Civil Engineering</department><CollegeCode>COLLEGE CODE</CollegeCode><DepartmentCode>CIVL</DepartmentCode><institution>Swansea University</institution><apcterm/><lastEdited>2020-12-17T10:40:31.1165861</lastEdited><Created>2019-09-12T04:27:43.4859122</Created><path><level id="1">Faculty of Science and Engineering</level><level id="2">School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Civil Engineering</level></path><authors><author><firstname>Ji</firstname><surname>Li</surname><orcid>0000-0003-4328-3197</orcid><order>1</order></author><author><firstname>Zhixian</firstname><surname>Cao</surname><order>2</order></author><author><firstname>Kaiheng</firstname><surname>Hu</surname><order>3</order></author><author><firstname>Gareth</firstname><surname>Pender</surname><order>4</order></author><author><firstname>Qingquan</firstname><surname>Liu</surname><order>5</order></author></authors><documents/><OutputDurs/></rfc1807>
spelling	2020-12-17T10:40:31.1165861 v2 51802 2019-09-12 A depth-averaged two-phase model for debris flows over erodible beds 4123c4ddbcd6e77f580974c661461c7c 0000-0003-4328-3197 Ji Li Ji Li true false 2019-09-12 CIVL Mass exchange between debris flow and the bed plays a vital role in debris flow dynamics. Here a depth-averaged two-phase model is proposed for debris flows over erodible beds. Compared to previous depth-averaged two-phase models, the present model features a physical step forward by explicitly incorporating the mass exchange between the flow and the bed. A widely used closure model in fluvial hydraulics is employed to estimate the mass exchange between the debris flow and the bed, and an existing relationship for bed entrainment rate is introduced for comparison. Also, two distinct closure models for the bed shear stresses are evaluated. One uses the Coulomb friction law and Manning’s equation to determine the solid and fluid resistances respectively, while the other employs an analytically derived formula for the solid phase and the mixing length approach for the fluid phase. A well-balanced numerical algorithm is applied to solve the governing equations of the model. The present model is first shown to reproduce average sediment concentrations in steady and uniform debris flows over saturated bed as compared to an existing formula underpinned by experimental datasets. Then, it is demonstrated to perform rather well as compared to the full set of USGS large-scale experimental debris flows over erodible beds, in producing debris flow depth, front location and bed deformation. The effects of initial conditions on debris flow mass and momentum gain are resolved by the present model, which explicitly demonstrates the roles of the wetness, porosity and volume of bed sediments in affecting the flow. By virtue of extended modeling cases, the present model produces debris flow efficiency that, as revealed by existing observations and empirical relations, increases with initial volume, which is enhanced by mass gain from the bed. Journal Article Earth Surface Processes and Landforms 43 4 817 839 0197-9337 debris flow; erodible bed; mass exchange; two-phase model; debris flow efficiency 30 3 2018 2018-03-30 10.1002/esp.4283 COLLEGE NANME Civil Engineering COLLEGE CODE CIVL Swansea University 2020-12-17T10:40:31.1165861 2019-09-12T04:27:43.4859122 Faculty of Science and Engineering School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Civil Engineering Ji Li 0000-0003-4328-3197 1 Zhixian Cao 2 Kaiheng Hu 3 Gareth Pender 4 Qingquan Liu 5
title	A depth-averaged two-phase model for debris flows over erodible beds
spellingShingle	A depth-averaged two-phase model for debris flows over erodible beds Ji Li
title_short	A depth-averaged two-phase model for debris flows over erodible beds
title_full	A depth-averaged two-phase model for debris flows over erodible beds
title_fullStr	A depth-averaged two-phase model for debris flows over erodible beds
title_full_unstemmed	A depth-averaged two-phase model for debris flows over erodible beds
title_sort	A depth-averaged two-phase model for debris flows over erodible beds
author_id_str_mv	4123c4ddbcd6e77f580974c661461c7c
author_id_fullname_str_mv	4123c4ddbcd6e77f580974c661461c7c_***_Ji Li
author	Ji Li
author2	Ji Li Zhixian Cao Kaiheng Hu Gareth Pender Qingquan Liu
format	Journal article
container_title	Earth Surface Processes and Landforms
container_volume	43
container_issue	4
container_start_page	817
publishDate	2018
institution	Swansea University
issn	0197-9337
doi_str_mv	10.1002/esp.4283
college_str	Faculty of Science and Engineering
hierarchytype
hierarchy_top_id	facultyofscienceandengineering
hierarchy_top_title	Faculty of Science and Engineering
hierarchy_parent_id	facultyofscienceandengineering
hierarchy_parent_title	Faculty of Science and Engineering
department_str	School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Civil Engineering{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Civil Engineering
document_store_str	0
active_str	0
description	Mass exchange between debris flow and the bed plays a vital role in debris flow dynamics. Here a depth-averaged two-phase model is proposed for debris flows over erodible beds. Compared to previous depth-averaged two-phase models, the present model features a physical step forward by explicitly incorporating the mass exchange between the flow and the bed. A widely used closure model in fluvial hydraulics is employed to estimate the mass exchange between the debris flow and the bed, and an existing relationship for bed entrainment rate is introduced for comparison. Also, two distinct closure models for the bed shear stresses are evaluated. One uses the Coulomb friction law and Manning’s equation to determine the solid and fluid resistances respectively, while the other employs an analytically derived formula for the solid phase and the mixing length approach for the fluid phase. A well-balanced numerical algorithm is applied to solve the governing equations of the model. The present model is first shown to reproduce average sediment concentrations in steady and uniform debris flows over saturated bed as compared to an existing formula underpinned by experimental datasets. Then, it is demonstrated to perform rather well as compared to the full set of USGS large-scale experimental debris flows over erodible beds, in producing debris flow depth, front location and bed deformation. The effects of initial conditions on debris flow mass and momentum gain are resolved by the present model, which explicitly demonstrates the roles of the wetness, porosity and volume of bed sediments in affecting the flow. By virtue of extended modeling cases, the present model produces debris flow efficiency that, as revealed by existing observations and empirical relations, increases with initial volume, which is enhanced by mass gain from the bed.
published_date	2018-03-30T04:03:48Z
_version_	1763753306629341184
score	11.037603

A depth-averaged two-phase model for debris flows over erodible beds

Similar Items