scholarly journals Interplay between grain protrusion and sediment entrainment in an experimental flume

2017 ◽  
Vol 122 (1) ◽  
pp. 274-289 ◽  
Author(s):  
Claire C. Masteller ◽  
Noah J. Finnegan
Keyword(s):  
Sediment Entrainment ◽  
Experimental Flume

scholarly journals Study on hydraulic resistance of erodible bed at the Chiyoda experimental flume

2014 ◽  
Vol 39 ◽  
pp. 81-87
Author(s):  
T. Kakinuma ◽  
T. Inoue ◽  
R. Akahori ◽  
A. Takeda
Keyword(s):  
Large Scale ◽  
Flow Distribution ◽  
Longitudinal Survey ◽  
Sand Wave ◽  
Vertical Flow ◽  
Sand Waves ◽  
Wave Development ◽  
Logarithmic Distribution ◽  
Steady Flow Condition ◽  
Experimental Flume

Abstract. The authors made erodible bed experiments under steady flow condition at the Chiyoda Experimental Flume, a large-scale facility constructed on the floodplain of the Tokachi River, and observed sand waves on the bed of the flume. In this study, the characteristics of the sand waves are examined along the longitudinal survey lines and confirmed to be dunes. Next, the authors estimated Manning's roughness coefficients from the observed hydraulic values and assumed that the rise of the coefficients attributed to the sand wave development. Finally, vertical flow distribution on the sand waves are examined, and observed velocity distribution on the crest of waves found to be explained by the logarithmic distribution theory.

Quantifying microplastic particle transport and retention in an experimental flume environment

2021 ◽  
Author(s):  
Jan-Pascal Boos ◽  
Benjamin Gilfedder ◽  
Sven Frei
Keyword(s):  
Particle Transport ◽  
Solid Phase ◽  
River Sediments ◽  
Time Resolved ◽  
Fluvial Systems ◽  
Particle Mobility ◽  
Hyporheic Flow ◽  
Scale Experiment ◽  
Streambed Sediments ◽  
Experimental Flume

<p>Rivers and streams are the dominant transport vectors for microplastic (MP) input into marine environments. During transport, complex physicochemical interactions between particles, water and river sediments influence particle mobility and retention. The specific transport mechanisms of MP in fluvial systems are not yet fully understood, and the main reason lies in the limitation in reliable data derived from experimental analysis.</p><p>In our subproject of the ‘CRC 1357 Microplastics’, we investigate the hydrodynamic mechanisms that control the transport and retention behavior of MP in open channel flows and streambed sediments. In an experimental flume environment, we create realistic hydrodynamic and hyporheic flow conditions by using various porous media (e.g. glass beads or sand) and bedform structures (e.g. riffle-pool sequences, ripples and dunes), modelled from real stream systems.</p><p>The method developed here can quantitatively analyze the transport of pore-scale particles (1-40 µm) based on fluorometric techniques. Particle velocity distributions and particle transport are measured using Particle-Image-Velocimetry and Laser-Doppler-Velocimetry. With our setup, we can quantitatively investigate time-resolved MP transport and retention through the aqueous and solid phase in a flume scale experiment.</p>

An experimental flume study on the formation of transverse ribs

1978 ◽  
Author(s):  
T J Day ◽  
B C McDonald
Keyword(s):  
Experimental Flume ◽  
Flume Study

scholarly journals Frazil-ice entrainment of sediment: large-tank laboratory experiments

2001 ◽  
Vol 47 (158) ◽  
pp. 461-471 ◽  
Author(s):  
Lars Henrik Smedsrud
Keyword(s):  
Laboratory Experiments ◽  
Surface Current ◽  
High Heat ◽  
Heat Fluxes ◽  
Vertical Diffusion ◽  
Turbulent Dissipation ◽  
Frazil Ice ◽  
Air Temperatures ◽  
Sediment Entrainment ◽  
Ice Production

AbstractLaboratory experiments that simulate natural ice-formation processes and sediment entrainment in shallow water are presented. A 10–30 cm s−1 current was forced with impellers in a 20 m long, 1 m deep indoor tank. Turbulence in the flow maintained a suspension of sediments at concentrations of 10–20 mg L−1 at 0.5 m depth. Low air temperatures (∼−15°C) and 5 m s−1 winds resulted in total upward heat fluxes in the range 140–260 W m−2. The cooling produced frazil-ice crystals up to 2 cm in diameter with concentrations up to 4.5 g L−1 at 0.5 m depth. Considerable temporal variability with time-scales of <1 min was documented. A close to constant portion of the smaller frazil crystals remained in suspension. After some hours the larger crystals, which made up most of the ice volume, accumulated as slush at the surface. Current measurements were used to calculate the turbulent dissipation rate, and estimates of vertical diffusion were derived. After 5–8 hours, sediment concentrations in the surface slush were normally close to those of the water. After 24 hours, however, they were 2–4 times higher. Data indicate that sediment entrainment depends on high heat fluxes and correspondingly high frazil-ice production rates, as well as sufficiently strong turbulence. Waves do not seem to increase sediment entrainment significantly.

Probability model for gravel sediment entrainment in turbulent flows

2013 ◽  
Vol 7 (3) ◽  
pp. 154-160 ◽  
Author(s):  
Jianmin Ma ◽  
Dong Xu ◽  
Yuchuan Bai ◽  
John J.R. Williams
Keyword(s):  
Turbulent Flows ◽  
Probability Model ◽  
Sediment Entrainment

scholarly journals Warm-based basal sediment entrainment and far-field Pleistocene origin evidenced in central Transantarctic blue ice through stable isotopes and internal structures

2018 ◽  
Vol 64 (244) ◽  
pp. 185-196 ◽  
Author(s):  
JOSEPH A. GRALY ◽  
KATHY J. LICHT ◽  
CHRISTINE M. KASSAB ◽  
BROXTON W. BIRD ◽  
MICHAEL R. KAPLAN
Keyword(s):  
Stable Isotopes ◽  
Ice Core ◽  
Far Field ◽  
Ice Flow ◽  
Air Bubble ◽  
Internal Structures ◽  
Flow Speeds ◽  
Sediment Entrainment ◽  
Stable Isotopes Of Water ◽  
Basal Melting

ABSTRACTStable isotopes of water (δ18O and δ2H) were measured in the debris-laden ice underlying an Antarctic blue ice moraine, and in adjoining Law Glacier in the central Transantarctic Mountains. Air bubble content and morphology were assessed in shallow ice core samples. Stable isotope measurements plot either on the meteoric waterline or are enriched from it. The data cluster in two groups: the ice underlying the moraine has a δ2H:δ18O slope of 5.35 ± 0.92; ice from adjoining portions of Law Glacier has a slope of 6.69 ± 1.39. This enrichment pattern suggests the moraine's underlying blue ice entrained sediment through refreezing processes acting in an open system. Glaciological conditions favorable to warm-based sediment entrainment occur 30–50 km upstream. Basal melting and refreezing are further evidenced by abundant vapor figures formed from internal melting of the ice crystals. Both the moraine ice and Law Glacier are sufficiently depleted of heavy isotopes that their ice cannot be sourced locally, but instead must be derived from far-field interior regions of the higher polar plateau. Modeled ice flow speeds suggest the ice must be at least 80 ka old, with Law Glacier's ice possibly dating to OIS 5 and moraine ice older still.

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