An improved formula for bed-load rate in open channel flows with emergent vegetation

Physics of Fluids, Journal Year: 2024, Volume and Issue: 36(1)

Published: Jan. 1, 2024

There is an urgent need to predict the bed-load transport rate in vegetated river ecosystems support restoration efforts. In response, we have developed a novel model for estimating effective shear stress acting on riverbed. This based energy equation and considers intrinsic relationship between loss mean flow turbulence generated by vegetation open channel flows with emergent vegetation. Using this bed model, assessed performance of Meyer-Peter–Müller (MPM) formula predicting comparing it collected literature experimental data. The results revealed that MPM does not provide accurate predictions. It tends overestimate when dimensionless approximately less than one underestimate them greater one. suggests enhances decreases sediment larger or lower one, respectively. Consequently, modified coefficients using extensive data, leading development predictive flows. new outperforms existing equations bedload rate, even umbrella-like

Language: Английский

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Quantifying Predictive Uncertainty and Feature Selection in River Bed Load Estimation: A Multi-Model Machine Learning Approach with Particle Swarm Optimization

Water, Journal Year: 2024, Volume and Issue: 16(14), P. 1945 - 1945

Published: July 10, 2024

This study presents a comprehensive multi-model machine learning (ML) approach to predict river bed load, addressing the challenge of quantifying predictive uncertainty in fluvial geomorphology. Six ML models—random forest (RF), categorical boosting (CAT), extra tree regression (ETR), gradient (GBM), Bayesian model (BRM), and K-nearest neighbors (KNNs)—were thoroughly evaluated across several performance metrics like root mean square error (RMSE), correlation coefficient (R). To enhance training optimize performance, particle swarm optimization (PSO) was employed for hyperparameter tuning all models, leveraging its capability efficiently explore complex spaces. Our findings indicated that RF, GBM, CAT, ETR demonstrate superior (R score > 0.936), benefiting significantly from PSO. In contrast, BRM displayed lower (0.838), indicating challenges with approaches. The feature importance analysis, including permutation SHAP values, highlighted non-linear interdependencies between variables, discharge (Q), slope (S), flow width (W) being most influential. also examined specific impact individual variables on by adding excluding which is particularly meaningful when choosing input model, especially limited data conditions. Uncertainty quantification through Monte Carlo simulations enhanced predictability reliability models larger datasets. increased improved precision evident consistent rise R scores reduction standard deviations as sample size increased. research underscored potential advanced ensemble methods PSO mitigate limitations single-predictor exploit collective strengths, thereby improving predictions load estimation. insights this provide valuable framework future directions focused optimizing configurations hydro-dynamic modeling.

Language: Английский

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Solute flow and particle transport in aquatic ecosystems: A review on the effect of emergent and rigid vegetation

Environmental Science and Ecotechnology, Journal Year: 2024, Volume and Issue: 21, P. 100429 - 100429

Published: May 10, 2024

In-channel vegetation is ubiquitous in aquatic environments and plays a critical role the fate transport of solutes particles ecosystems. Recent studies have advanced our understanding solute flow particle This review summarizes these papers discusses impacts emergent rigid on surface flow, advection dispersion solutes, suspended load transport, bedload hyporheic exchange. The two competing effects above processes are discussed. On one hand, reduces mean velocity at same slope, which mass transport. other velocity, generates turbulence, enhances Mechanistic predictive equations derived from laboratory experiments Predictive for turbulent kinetic energy inside an canopy based force balance. advection-dispersion process, exchange summarized. vegetation-related factors, such as morphology, submergence, flexibility, briefly transporting particles, micro- macro-plastics, also Finally, suggestions future research directions proposed to advance dynamic interplays among natural vegetation, dynamics, sedimentary processes.

Language: Английский

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Flow in multi-layered vegetated compound channels with different bank slopes

Physics of Fluids, Journal Year: 2023, Volume and Issue: 35(3)

Published: Feb. 20, 2023

Bank angle and floodplain vegetation emergence determine the flow nature in a compound channel. Two sets of 45° 90° bank channel is considered present work. Each set considers three cases arrangements: no vegetation, multi-layered fully submerged, partially emergent. The characteristics like velocity, Reynolds shear stress (RSS), turbulent kinetic energy (TKE) do not vary much cross section absence vegetation. However, with slopes nearby region are affected most as it acts an intermediary between main floodplain. An analysis anisotropic invariant map shows dominance transverse component compared to velocity around higher for steep (90°) gradual slope (45°) streamwise RSS bursting events also show magnitude near bed sloping region. This indicates instability banks slopes. increase affects TKE greater vulnerability presence emergence. From hydraulic engineering perspective, this study will be helpful field understanding failure ways maintain their stability.

Language: Английский

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MPS-based simulation of dam-break wave propagation over wet beds with a sediment layer

Ocean Engineering, Journal Year: 2023, Volume and Issue: 281, P. 115035 - 115035

Published: June 7, 2023

Language: Английский

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Hydrodynamics in channels with partial vegetation cover: Investigating the effects of homogeneous and heterogeneous vertical vegetation distribution

Advances in Water Resources, Journal Year: 2024, Volume and Issue: 185, P. 104642 - 104642

Published: Feb. 1, 2024

Language: Английский

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Bed Shear Stress and Near‐Bed Flow Through Sparse Arrays of Rigid Emergent Vegetation

Water Resources Research, Journal Year: 2024, Volume and Issue: 60(4)

Published: April 1, 2024

Abstract Vegetation is an essential component of natural rivers and has significant effects on flow morphodynamic processes. Although progress been made in characterizing resistance vegetated flows, the impact vegetation bed shear stress, a key driver sediment transport, still needs better characterization understanding. This research, explores stress near‐bed characteristics sparse arrays rigid emergent cylinders mimicking over rough bed. For this purpose, novel adaptation plate was used to measure at canopy scale. These measurements were analyzed relation spatially averaged quantities for different array densities. The results show that, constant water depth, investigated cylinder enhances ratio between bulk velocity (i.e., Darcy‐Weisbach friction factor) compared unobstructed open‐channel that increases with density. Moreover, higher velocities observed On other hand, no influence values turbulent kinetic energy stresses observed. Finally, it shown thickness layer suitable parameter scale flows.

Language: Английский

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An analytical study for predicting incipient motion velocity of sediments under ice cover

Scientific Reports, Journal Year: 2025, Volume and Issue: 15(1)

Published: Jan. 14, 2025

This study investigates the critical impact of incipient sediment motion on transport estimation and riverbed evolution prediction. In this research, we examine effects ice cover vertical distribution flow velocity, establishing a mathematical relationship between average velocities in open channel ice-covered flows. leads to derivation formula for velocity under cover. Additionally, analyzes process jam conditions. The proposed is applicable both flows, effectively capturing characteristics non-cohesive cohesive sediments. calculated closely align with empirical data from existing literature. reveals that roughness significantly influences sediment, higher ratios promoting initiation more favorable hydraulic Furthermore, beneath jams experiences significant scouring. Field observations indicate when form localized sections river, displacement main can substantially increase areas away jam, leading scouring non-ice-jammed sedimentation ice-jammed areas. uneven likely factor contributing discrepancies theoretical predictions observed outcomes. complexity limited associated sediments pose challenges validating these types.

Language: Английский

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Regulating effect of wooded channels on debris flows

Landslides, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 6, 2025

Language: Английский

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Morphodynamics of mobile dunes with downward seepage

Physics of Fluids, Journal Year: 2025, Volume and Issue: 37(2)

Published: Feb. 1, 2025

The experimental study examines the flow dynamics and sediment transport behavior of mobile dune-shaped bedforms induced by downward seepage. longitudinal velocities in stream direction, Reynolds shear stresses (RSS), energy budget, transitional probabilities turbulence bursting events were analyzed without with Application seepage discharge significantly altered patterns, increasing streamwise magnitude RSS on gradually rising face reducing them at crest trailing section bedform. Downward intensifies dissipation diffusion steep slip side dune due to enhanced circulation, which encourages scour hole formation. However, proximity bed initial region surface leeward sections features, turbulent production surges substantially With seepage, anisotropy invariant map shows a shift patterns from two-dimensional (2D) one-dimensional middle sections, while 2D anisotropy. Enhanced transition outward interaction sweep intensify under conditions, vortex strength promoting erosion mobilization conditions. Scour depth over time both no-seepage greater observed Sediment rates also higher than no

Language: Английский

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