Dynamics of Hyporheic Exchange Flux and Fine Particle Deposition Under Moving Bedforms

AbstractWhile the ecological significance of hyporheic exchange and fine particle transport in rivers is well established, these processes are generally considered irrelevant to riverbed morphodynamics. We show that coupling between hyporheic exchange, suspended sediment deposition, and sand bedform motion strongly modulates morphodynamics and sorts bed sediments. Hyporheic exchange focuses fine-particle deposition within and below mobile bedforms, which suppresses bed mobility. However, deposited fines are also remobilized by bedform motion, providing a mechanism for segregating coarse and fine particles in the bed. Surprisingly, two distinct end states emerge from the competing interplay of bed stabilization and remobilization: a locked state in which fine particle deposition completely stabilizes the bed, and a dynamic equilibrium in which frequent remobilization sorts the bed and restores mobility. These findings demonstrate the significance of hyporheic exchange to riverbed morphodynamics and clarify how dynamic interactions between coarse and fine particles produce sedimentary patterns commonly found in rivers.

Download Full-text

Bedform segregation and locking increase storage of natural and synthetic particles in rivers

10.31223/x5jc9k ◽

2021 ◽

Author(s):

Jonathan Dallmann ◽

Colin Phillips ◽

Yoni Teitelbaum ◽

Edwin Saavedra Cifuentes ◽

Nicole Sund ◽

...

Keyword(s):

Suspended Sediment ◽

Fine Particle ◽

Particle Deposition ◽

Fine Particles ◽

Dynamic Equilibrium ◽

Hyporheic Exchange ◽

Ecological Significance ◽

Dynamic Interactions ◽

Bed Sediments ◽

Bed Mobility

While the ecological significance of hyporheic exchange and fine particle transport in rivers is well established, these processes are generally considered irrelevant to riverbed morphodynamics. We show that coupling between hyporheic exchange, suspended sediment deposition, and sand bedform motion strongly modulates morphodynamics and sorts bed sediments. Hyporheic exchange focuses fine-particle deposition within and below mobile bedforms, which suppresses bed mobility. However, deposited fines are also remobilized by bedform motion, providing a mechanism for segregating coarse and fine particles in the bed. Surprisingly, two distinct end states emerge from the competing interplay of bed stabilization and remobilization: a locked state in which fine particle deposition completely stabilizes the bed, and a dynamic equilibrium in which frequent remobilization sorts the bed and restores mobility. These findings demonstrate the significance of hyporheic exchange to riverbed morphodynamics and clarify how dynamic interactions between coarse and fine particles produce sedimentary patterns commonly found in rivers

Download Full-text

Numerical Simulation of Powder Dispersion Performance by Different Mesh Types

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.680.82 ◽

2016 ◽

Vol 680 ◽

pp. 82-85

Author(s):

Jian Cai ◽

Lan Chen ◽

Umezuruike Linus Opara

Keyword(s):

Numerical Simulation ◽

Flow Field ◽

Fine Particle ◽

Particle Deposition ◽

Tetrahedral Mesh ◽

Computational Time ◽

Kinetic Characteristics ◽

Powder Dispersion ◽

Simulation Results ◽

Time Accuracy

OBJECTIVE To investigate the influence of mesh type on numerical simulating the dispersion performance of micro-powders through a home-made tube. METHODS With the computational fluid dynamics (CFD) method, a powder dispersion tube was meshed in three different types, namely, tetrahedral, unstructured hexahedral and prismatic-tetrahedral hybrid meshes. The inner flow field and the kinetic characteristics of the particles were investigated. Results of the numerical simulation were compared with literature evidences. RESULTS The results showed that using tetrahedral mesh had the highest computational efficiency, while employing the unstructured hexahedral mesh obtained more accurate outlet velocity. The simulation results of the inner flow field and the kinetic characteristics of the particles were slightly different among the three mesh types. The calculated particle velocity using the tetrahedral mesh had the best correlation with the changing trend of the fine particle mass in the first 4 stages of the new generation impactor (NGI) (R2 = 0.91 and 0.89 for powder A and B, respectively). Conclusions Mesh type affected computational time, accuracy of simulation results and the prediction abilities of fine particle deposition.

Download Full-text

Experimental study on fine particle deposition in supercritical water natural circulation

Progress in Nuclear Energy ◽

10.1016/j.pnucene.2021.103981 ◽

2021 ◽

Vol 141 ◽

pp. 103981

Author(s):

Zhou Tao ◽

Ning Chen ◽

Cheng Hu ◽

Liangyu Zhu ◽

Juan Chen

Keyword(s):

Experimental Study ◽

Supercritical Water ◽

Fine Particle ◽

Particle Deposition ◽

Natural Circulation

Download Full-text

Effect of Body Size on Breathing Pattern and Fine-particle Deposition in Children.

Cardiopulmonary Physical Therapy Journal ◽

10.1097/01823246-200415040-00005 ◽

2004 ◽

Vol 15 (4) ◽

pp. 22

Author(s):

W D Bennett ◽

K L. Zeman

Keyword(s):

Body Size ◽

Fine Particle ◽

Particle Deposition ◽

Breathing Pattern

Download Full-text

Three-way coupling of fine particle deposition behavior on a rib-roughened surface

Powder Technology ◽

10.1016/j.powtec.2020.06.021 ◽

2020 ◽

Vol 372 ◽

pp. 420-427 ◽

Cited By ~ 1

Author(s):

Wenpeng Hong ◽

Yan Liu ◽

Bihui Wang ◽

Haoran Li

Keyword(s):

Fine Particle ◽

Particle Deposition ◽

Deposition Behavior ◽

Roughened Surface ◽

Rib Roughened

Download Full-text

Seasonal variations in surface water groundwater interaction alter the relation of solute transport and biogeochemical processes in the hyporheic zone

10.5194/egusphere-egu21-2949 ◽

2021 ◽

Author(s):

Lara-Maria Schmitgen ◽

Tobias Schuetz

Keyword(s):

Surface Water ◽

Boundary Conditions ◽

Hyporheic Zone ◽

Treatment Plant ◽

Hyporheic Exchange ◽

Waste Water Treatment Plant ◽

Small Scale ◽

Vertical Profiles ◽

Surface Water And Groundwater ◽

Exchange Flux

<p>The hyporheic interstitial as interface between surface water and groundwater offers a unique environment for contaminant attenuation and nutrient cycling, with steep chemical gradients and high retention times. Disentangling the effect of seasonal dynamics in exchange flux intensities and directions, we carried out 19 measurement campaigns where we sampled the continuum surface water - hyporheic zone - groundwater and the climatic and hydraulic boundary conditions of a whole year. Groundwater, surface water and hyporheic zone pore water from four depths were sampled at two vertical profiles in a second order stream about 150 m downstream a municipal waste water treatment plant effluent. Samples were analyzed for physical water parameters, major anions, ammonium, iron, manganese, NPOC and five selected pharmaceuticals (diclofenac, carbamazepine, caffeine, ethinylestradiol and clofibric acid). Surface water and groundwater levels as well as river discharge were measured to quantify the hydraulic boundary conditions. In addition, three vertical profiles, each equipped with five newly developed probes (Truebner AG) allowed a parallel monitoring of continuous bulk water temperatures and bulk electrical conductivity dynamics over two years. Furthermore, continuous hyporheic exchange flux intensities and exchange depths were calculated using analytical and numerical model schemes to allow distinguishing between small scale transport and attenuation processes.</p><p>The typical behavior of the redox sensitive metals and nutrients with depth is visible in each single profile snapshot. The picture is not as clear for the examined pharmaceuticals, because dilution has a major effect on the observable low concentrations. However, a clear seasonal variation driven by hydraulic and climatic processes can be observed for all substances. We were able to trace the organic pollutants down to the groundwater. Furthermore, the influence of hyporheic exchange flux intensities and directions on nutrient and contaminant depth profiles is shown.</p>

Download Full-text

Development of a New Continuous Monitor for Nonvolatile Solute in Ultrapure Water by Atomization

Journal of the IEST ◽

10.17764/jiet.1.30.4.q03m5684126921nq ◽

1987 ◽

Vol 30 (4) ◽

pp. 39-42

Author(s):

Y. Kousaka ◽

T. Niida ◽

Y. Tanaka ◽

Y. Sato ◽

H. Kano ◽

...

Keyword(s):

Theoretical Analysis ◽

Fine Particle ◽

Particle Deposition ◽

Aerosol Particles ◽

Condensation Nucleus ◽

Measuring Method ◽

Number Concentration ◽

Ultrapure Water ◽

Particle Counter ◽

Continuous Monitor

A new monitoring system has been developed for continuously measuring the concentration of total nonvolatile impurities in ultrapure water. The measuring method is based on the principle of determining the Residue After Evaporation (RAE) of atomized droplets, taking account of the particle deposition loss. The system consists of a water atomizing unit, a droplet evaporating and drying unit, an air diluter, a fine particle counter, etc. For the particle counter, a Condensation Nucleus Counter (CMC) is used; this counter is a mixing type, able to detect particles larger than 0.01 μm. It is verified from both the theoretical analysis and the experimental results that this monitor can rapidly detect very low impurity concentrations by counting the number concentration of aerosol particles.

Download Full-text