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Teng, Penghua
Publications (2 of 2) Show all publications
Teng, P., Johansson, F. & Hellström, J. G. (2023). Modelling erosion of a single rock block using a coupled CFD-DEM approach. Journal of Rock Mechanics and Geotechnical Engineering, 15(9), 2375-2387
Open this publication in new window or tab >>Modelling erosion of a single rock block using a coupled CFD-DEM approach
2023 (English)In: Journal of Rock Mechanics and Geotechnical Engineering, ISSN 1674-7755, Vol. 15, no 9, p. 2375-2387Article in journal (Refereed) Published
Abstract [en]

Rock block removal is the prevalent physical mechanism for rock erosion and could affect the stability of dam foundations and spillways. Despite this, understanding of block removal is still inadequate because of the complex interactions among block characteristics, hydraulic forces, and erosive processes acting on the block. Herein, based on a previously conducted physical experiment of erosion of a single rock block, the removal processes of two different protruding blocks are represented by a coupled computational fluid dynamics-discrete element model (CFD-DEM) approach under varied flow conditions. Additionally, the blocks could be rotated with respect to the flow direction to consider the effect of the discontinuity orientation on the block removal process. Simulation results visualize the entire block removal process. The simulations reproduce the effects of the discontinuity orientation on the critical flow velocity inducing block incipient motion and the trajectory of the block motion observed in the physical experiments. The numerical results present a similar tendency of the critical velocities at different discontinuity orientations but have slightly lower values. The trajectory of the block in the simulations fits well with the experimental measurements. The relationship between the dimensionless critical shear stress and discontinuity orientation observed from the simulations shows that the effect of block protrusion becomes more dominant on the block incipient motion with the increase of relative protrusion height. To our knowledge, this present study is the first attempt to use the coupled finite volume method (FVM)-DEM approach for modelling the interaction behavior between the block and the flowing water so that the block removal process can be reproduced and analyzed.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Rock erosion, Block removal, Incipient motion, Coupled CFD-DEM, Critical shear stress
National Category
Fluid Mechanics and Acoustics
Research subject
Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-99600 (URN)10.1016/j.jrmge.2023.06.001 (DOI)001070906500014 ()2-s2.0-85164369936 (Scopus ID)
Note

Validerad;2023;Nivå 2;2023-11-07 (joosat);

Full text license: CC BY

Funder: Swedish Hydropower Centre

Available from: 2023-08-14 Created: 2023-08-14 Last updated: 2024-03-07Bibliographically approved
Teng, P., Hellström, J. G., Johansson, F. & Nilsson, C.-O. (2023). Modelling of erosion in rock spillway channels. In: : . Paper presented at Canadian Dam Association (CDA) 2023 Annual Conference & Trade Show, Winnipeg, Manitoba, Canada, October 22-25, 2023. Canadian Dam Association (CDA)
Open this publication in new window or tab >>Modelling of erosion in rock spillway channels
2023 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Erosion of rock channels downstream spillways may cause the significant deterioration of the spillways, raisingconcern for the safety of the dam. To evaluate the occurrence of rock erosion, this paper aims to employ a resolvedComputational Fluid Dynamics (CFD)-Discrete Element Method (DEM) approach to model the erosion process of asingle rock block and to investigate the effects of different parameters. The approach models the interaction behaviorsbetween flowing water and rock blocks. Simulation results visualize the erosion process of the rock block, whichprovides a reference to determine the threshold of the initiation of rock erosion. The results show that the incipientmotion of the rock block is significantly affected by the joint aperture. With the increase of the joint aperture size, thepressure distribution on the block surface is altered. Simulation results of the rough channel model are compared witha smooth model, which points out the influence of channel roughness on the rock erosion process.

Abstract [fr]

Lérosion des canaux rocheux en aval des déversoirs peut entraîner une détérioration importante des déversoirs, ce quisoulève des inquiétudes quant à la sécurité du barrage. Pour évaluer simplement loccurrence de lérosion rocheuse, cetarticle vise à utiliser une approche résolue de la dynamique des fluides computationnelle (CFD)-méthode des élémentsdiscrets (DEM) pour modéliser le processus dérosion dun seul bloc de roche et pour étudier les effets de différentsparamètres. Lapproche modélise les comportements dinteraction entre leau courante et les blocs rocheux. Les résultatsde la simulation visualisent le processus dérosion du bloc rocheux, ce qui fournit une référence pour déterminer leseuil de l’initiation de lérosion . Les résultats montrent que le mouvement initial du bloc rocheux est significativementaffecté par louverture du joint. Avec laugmentation de la taille de louverture du joint, la répartition de la pression surla surface du bloc est modifiée. Les résultats de simulation du modèle de canal rugueux sont comparés à un modèlelisse, ce qui souligne linfluence significative de la rugosité du canal sur le processus dérosion de la roche

Place, publisher, year, edition, pages
Canadian Dam Association (CDA), 2023
Keywords
Spillway, Dam Safety, Rock Erosion, CFDEM
National Category
Geotechnical Engineering Other Civil Engineering
Research subject
Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-102359 (URN)
Conference
Canadian Dam Association (CDA) 2023 Annual Conference & Trade Show, Winnipeg, Manitoba, Canada, October 22-25, 2023
Available from: 2023-11-09 Created: 2023-11-09 Last updated: 2024-01-12Bibliographically approved
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