TY - JOUR
T1 - On the process of fine sediment infiltration into static gravel bed
T2 - A CFD–DEM modelling perspective
AU - Jaiswal, Atul
AU - Bui, Minh Duc
AU - Rutschmann, Peter
N1 - Publisher Copyright:
© 2023 The Authors. River Research and Applications published by John Wiley & Sons Ltd.
PY - 2024/1
Y1 - 2024/1
N2 - The gravel bed clogging, caused by infiltration and accumulation of fine sediment, degrades the river ecology. A proper understanding of the infiltration process, and underlying mechanism and causes, are necessary to take preventive measures. The process of fine sediment infiltration into static gravel bed is studied by distinguishing between bridging and percolation behaviours, as they affect the river ecology and physical processes occurring in the river system differently. However, several contradicting observations, concerning their occurrences, are reported. We employed the unresolved CFD–DEM method to simulate and investigate the infiltration process. The theoretical size ratios, corresponding to different geometrical configurations for a binary mixture of mono-disperse spherical particles, representing bridging and percolation processes, are considered and simulated with and without flowing water effects. The effects of several turbulence models on the infiltration process are also studied. We found that fine sediment infiltration in fluvial deposits is mainly gravity-dominated, supporting Cui's hypothesis that fine sediment infiltration through intra-gravel flow is similar to fine sediment infiltration driven by gravity. In contrast to consensus in the field, our results demonstrate that the occurrences of different infiltration processes (bridging and percolation) seem to be independent of gravel bed thickness, rather depend only on the relative grain size distribution of fine sediment and gravel. However, a precise definition of a ‘thick enough’ gravel bed is necessary to distinguish between bridging and percolation behaviours. Here, we hypothesize a suitable gravel bed thickness, which might be regarded as a ‘thick enough’ gravel bed.
AB - The gravel bed clogging, caused by infiltration and accumulation of fine sediment, degrades the river ecology. A proper understanding of the infiltration process, and underlying mechanism and causes, are necessary to take preventive measures. The process of fine sediment infiltration into static gravel bed is studied by distinguishing between bridging and percolation behaviours, as they affect the river ecology and physical processes occurring in the river system differently. However, several contradicting observations, concerning their occurrences, are reported. We employed the unresolved CFD–DEM method to simulate and investigate the infiltration process. The theoretical size ratios, corresponding to different geometrical configurations for a binary mixture of mono-disperse spherical particles, representing bridging and percolation processes, are considered and simulated with and without flowing water effects. The effects of several turbulence models on the infiltration process are also studied. We found that fine sediment infiltration in fluvial deposits is mainly gravity-dominated, supporting Cui's hypothesis that fine sediment infiltration through intra-gravel flow is similar to fine sediment infiltration driven by gravity. In contrast to consensus in the field, our results demonstrate that the occurrences of different infiltration processes (bridging and percolation) seem to be independent of gravel bed thickness, rather depend only on the relative grain size distribution of fine sediment and gravel. However, a precise definition of a ‘thick enough’ gravel bed is necessary to distinguish between bridging and percolation behaviours. Here, we hypothesize a suitable gravel bed thickness, which might be regarded as a ‘thick enough’ gravel bed.
KW - bridging
KW - fine sediment infiltration
KW - static gravel bed
KW - unimpeded static percolation
KW - unresolved CFD–DEM
UR - http://www.scopus.com/inward/record.url?scp=85173671098&partnerID=8YFLogxK
U2 - 10.1002/rra.4215
DO - 10.1002/rra.4215
M3 - Article
AN - SCOPUS:85173671098
SN - 1535-1459
VL - 40
SP - 29
EP - 48
JO - River Research and Applications
JF - River Research and Applications
IS - 1
ER -