scholarly journals Recalculation of bedload transport observations in Swiss mountain rivers using the model sedFlow

2014 ◽  
Vol 2 (2) ◽  
pp. 773-822 ◽  
Author(s):  
F. U. M. Heimann ◽  
D. Rickenmann ◽  
M. Böckli ◽  
A. Badoux ◽  
J. M. Turowski ◽  
...  
Keyword(s):  
Sensitivity Study ◽  
Bedload Transport ◽  
Transport Processes ◽  
Estimation Methods ◽  
Mountain Streams ◽  
Good Representation ◽  
Mountain Rivers ◽  
Practical Applications ◽  
Transport Dynamics ◽  
Routing Schemes

Abstract. Only few validated numeric models are available for the simulation of bedload transport dynamics in mountain streams. In this study, the recently developed modelling tool sedFlow has been applied to simulate bedload transport in two Swiss mountain streams. It is shown that sedFlow can be used to successfully reproduce observations from historic bedload transport events with reasonable parameter set-ups. The simulation results shed light on the difficulties that arise with traditional flow resistance estimation methods when macro-roughness is present. In addition, our results demonstrate that greatly simplified hydraulic routing schemes, such as kinematic wave or uniform discharge approaches, are probably sufficient for a good representation of bedload transport processes in steep mountain streams. The influence of different parameters is qualitatively evaluated in a simple sensitivity study. This proof-of-concept study demonstrates the usefulness of sedFlow for a range of practical applications in alpine mountain streams.

scholarly journals Calculation of bedload transport in Swiss mountain rivers using the model sedFlow: proof of concept

2015 ◽  
Vol 3 (1) ◽  
pp. 35-54 ◽  
Author(s):  
F. U. M. Heimann ◽  
D. Rickenmann ◽  
M. Böckli ◽  
A. Badoux ◽  
J. M. Turowski ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Goodness Of Fit ◽  
Bedload Transport ◽  
Transport Processes ◽  
Estimation Methods ◽  
Mountain Streams ◽  
Proof Of Concept ◽  
Mountain Rivers ◽  
Total Transport ◽  
Simulation Results

Abstract. Fully validated numerical models specifically designed for simulating bedload transport dynamics in mountain streams are rare. In this study, the recently developed modelling tool sedFlow has been applied to simulate bedload transport in the Swiss mountain rivers Kleine Emme and Brenno. It is shown that sedFlow can be used to successfully reproduce observations from historic bedload transport events with plausible parameter set-ups, meaning that calibration parameters are only varied within ranges of uncertainty that have been pre-determined either by previous research or by field observations in the simulated study reaches. In the Brenno river, the spatial distribution of total transport volumes has been reproduced with a Nash–Sutcliffe goodness of fit of 0.733; this relatively low value is partially due to anthropogenic extraction of sediment that was not considered. In the Kleine Emme river, the spatial distribution of total transport volumes has been reproduced with a goodness of fit of 0.949. The simulation results shed light on the difficulties that arise with traditional flow-resistance estimation methods when macro-roughness is present. In addition, our results demonstrate that greatly simplified hydraulic routing schemes, such as kinematic wave or uniform discharge approaches, are probably sufficient for a good representation of bedload transport processes in reach-scale simulations of steep mountain streams. The influence of different parameters on simulation results is semi-quantitatively evaluated in a simple sensitivity study. This proof-of-concept study demonstrates the usefulness of sedFlow for a range of practical applications in alpine mountain streams.

scholarly journals sedFlow – an efficient tool for simulating bedload transport, bed roughness, and longitudinal profile evolution in mountain streams

2014 ◽  
Vol 2 (2) ◽  
pp. 733-772 ◽  
Author(s):  
F. U. M. Heimann ◽  
D. Rickenmann ◽  
J. M. Turowski ◽  
J. W. Kirchner
Keyword(s):  
Grain Size ◽  
Size Fraction ◽  
Bedload Transport ◽  
Mountain Streams ◽  
Size Distributions ◽  
Roughness Effects ◽  
Efficient Tool ◽  
Transport Dynamics ◽  
Grain Size Distributions ◽  
Bed Roughness

Abstract. Especially in mountainuous environments, the prediction of sediment dynamics is important for managing natural hazards, assessing in-stream habitats, and understanding geomorphic evolution. We present the new modelling tool sedFlow for simulating fractional bedload transport dynamics in mountain streams. The model can deal with the effects of adverse slopes and uses state of the art approaches for quantifying macro-roughness effects in steep channels. Local grain size distributions are dynamically adjusted according to the transport dynamics of each grain size fraction. The tool sedFlow features fast calculations and straightforward pre- and postprocessing of simulation data. The model is provided together with its complete source code free of charge under the terms of the GNU General Public License (www.wsl.ch/sedFlow). Examples of the application of sedFlow are given in a companion article by Heimann et al. (2014).

scholarly journals sedFlow – a tool for simulating fractional bedload transport and longitudinal profile evolution in mountain streams

2015 ◽  
Vol 3 (1) ◽  
pp. 15-34 ◽  
Author(s):  
F. U. M. Heimann ◽  
D. Rickenmann ◽  
J. M. Turowski ◽  
J. W. Kirchner
Keyword(s):  
Grain Size ◽  
Size Fraction ◽  
Bedload Transport ◽  
Mountain Streams ◽  
Stream Channels ◽  
Roughness Effects ◽  
Current Application ◽  
Transport Dynamics ◽  
Climate Change Effects ◽  
Simulation Speed

Abstract. Especially in mountainous environments, the prediction of sediment dynamics is important for managing natural hazards, assessing in-stream habitats and understanding geomorphic evolution. We present the new modelling tool {sedFlow} for simulating fractional bedload transport dynamics in mountain streams. sedFlow is a one-dimensional model that aims to realistically reproduce the total transport volumes and overall morphodynamic changes resulting from sediment transport events such as major floods. The model is intended for temporal scales from the individual event (several hours to few days) up to longer-term evolution of stream channels (several years). The envisaged spatial scale covers complete catchments at a spatial discretisation of several tens of metres to a few hundreds of metres. sedFlow can deal with the effects of streambeds that slope uphill in a downstream direction and uses recently proposed and tested approaches for quantifying macro-roughness effects in steep channels. sedFlow offers different options for bedload transport equations, flow-resistance relationships and other elements which can be selected to fit the current application in a particular catchment. Local grain-size distributions are dynamically adjusted according to the transport dynamics of each grain-size fraction. sedFlow features fast calculations and straightforward pre- and postprocessing of simulation data. The high simulation speed allows for simulations of several years, which can be used, e.g., to assess the long-term impact of river engineering works or climate change effects. In combination with the straightforward pre- and postprocessing, the fast calculations facilitate efficient workflows for the simulation of individual flood events, because the modeller gets the immediate results as direct feedback to the selected parameter inputs. The model is provided together with its complete source code free of charge under the terms of the GNU General Public License (GPL) (www.wsl.ch/sedFlow). Examples of the application of sedFlow are given in a companion article by Heimann et al. (2015).

scholarly journals SOC Estimation of Lead Carbon Batteries Based on the Operating Conditions of an Energy Storage System in a Microgrid System

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 33
Author(s):  
Yuanyuan Chen ◽  
Zilong Yang ◽  
Yibo Wang
Keyword(s):  
Wavelet Transform ◽  
Energy Storage ◽  
Storage System ◽  
Estimation Method ◽  
Energy Storage System ◽  
Operating Conditions ◽  
Estimation Methods ◽  
Extend Kalman Filter ◽  
Practical Applications ◽  
Soc Estimation

The environment for practical applications of an energy storage system (ESS) in a microgrid system is very harsh, and therefore actual operating conditions become complex and changeable. In addition, the signal of the ESS sampling process contains a great deal of system and measurement noise, the sampled current fluctuates significantly, and also has high frequency. In this case, under such conditions, it is difficult to accurately estimate the state of charge (SOC) of the batteries in the ESS by common estimation methods. Therefore, this study proposes a compound SOC estimation method based on wavelet transform. This algorithm is very suitable for microgrid systems with large current, frequent fluctuating conditions, and high noise interference. The experimental results and engineering data show that the relative error of the method is 0.5%, which is much lower than the extend Kalman filter (EKF) based on wavelet transform.

scholarly journals Fundamental aspects of electrochemically controlled wetting of nanoscale composite materials

2017 ◽  
Vol 199 ◽  
pp. 75-99 ◽  
Author(s):  
A. Robert Hillman ◽  
Karl S. Ryder ◽  
Hani K. Ismail ◽  
Asuman Unal ◽  
Annelies Voorhaar
Keyword(s):  
Ionic Liquid ◽  
Composite Materials ◽  
Composite Films ◽  
Transport Processes ◽  
Electronic Charge ◽  
Energy Storage Devices ◽  
Protic Ionic Liquid ◽  
Practical Applications ◽  
Wave Measurements ◽  
Multi Walled Carbon Nanotubes

Electroactive films based on conducting polymers have numerous potential applications, but practical devices frequently require a combination of properties not met by a single component. This has prompted an extension to composite materials, notably those in which particulates are immobilised within a polymer film. Irrespective of the polymer and the intended application, film wetting is important: by various means, it facilitates transport processes – of electronic charge, charge-balancing counter ions (“dopant”) and analyte/reactant molecules – and motion of polymer segments. While film solvent content and transfer have been widely studied for pristine polymer films exposed to molecular solvents, extension to non-conventional solvents (such as ionic liquids) or to composite films has been given much less attention. Here we consider such cases based on polyaniline films. We explore two factors, the nature of the electrolyte (solvent and film-permeating ions) and the effect of introducing particulate species into the film. In the first instance, we compare film behaviours when exposed to a conventional protic solvent (water) with an aprotic ionic liquid (Ethaline) and the intermediate case of a protic ionic liquid (Oxaline). Secondly, we explore the effect of inclusion of physically diverse particulates: multi-walled carbon nanotubes, graphite or molybdenum dioxide. We use electrochemistry to control and monitor the film redox state and change therein, and acoustic wave measurements to diagnose rheologicallyvs.gravimetrically determined response. The outcomes provide insights of relevance to future practical applications, including charge/discharge rates and cycle life for energy storage devices, “salt” transfer in water purification technologies, and the extent of film “memory” of previous environments when sequentially exposed to different media.

scholarly journals Passive acoustic measurement of bedload grain size distribution using self-generated noise

2018 ◽  
Vol 22 (1) ◽  
pp. 767-787 ◽  
Author(s):  
Teodor Petrut ◽  
Thomas Geay ◽  
Cédric Gervaise ◽  
Philippe Belleudy ◽  
Sebastien Zanker
Keyword(s):  
Grain Size ◽  
Sediment Transport ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Measurement Techniques ◽  
Bedload Transport ◽  
Transport Processes ◽  
Signal Spectrum ◽  
Inversion Method ◽  
Passive Acoustic

Abstract. Monitoring sediment transport processes in rivers is of particular interest to engineers and scientists to assess the stability of rivers and hydraulic structures. Various methods for sediment transport process description were proposed using conventional or surrogate measurement techniques. This paper addresses the topic of the passive acoustic monitoring of bedload transport in rivers and especially the estimation of the bedload grain size distribution from self-generated noise. It discusses the feasibility of linking the acoustic signal spectrum shape to bedload grain sizes involved in elastic impacts with the river bed treated as a massive slab. Bedload grain size distribution is estimated by a regularized algebraic inversion scheme fed with the power spectrum density of river noise estimated from one hydrophone. The inversion methodology relies upon a physical model that predicts the acoustic field generated by the collision between rigid bodies. Here we proposed an analytic model of the acoustic energy spectrum generated by the impacts between a sphere and a slab. The proposed model computes the power spectral density of bedload noise using a linear system of analytic energy spectra weighted by the grain size distribution. The algebraic system of equations is then solved by least square optimization and solution regularization methods. The result of inversion leads directly to the estimation of the bedload grain size distribution. The inversion method was applied to real acoustic data from passive acoustics experiments realized on the Isère River, in France. The inversion of in situ measured spectra reveals good estimations of grain size distribution, fairly close to what was estimated by physical sampling instruments. These results illustrate the potential of the hydrophone technique to be used as a standalone method that could ensure high spatial and temporal resolution measurements for sediment transport in rivers.

scholarly journals Numerical simulation of bedload tracer transport associated with sand bar formation, bank erosion, and channel migration

2018 ◽  
Vol 40 ◽  
pp. 02013
Author(s):  
Toshiki Iwasaki ◽  
Satomi Yamaguchi ◽  
Hiroki Yabe
Keyword(s):  
Numerical Model ◽  
Bank Erosion ◽  
Bedload Transport ◽  
Transport Processes ◽  
Tracer Transport ◽  
Channel Migration ◽  
River Systems ◽  
Sand Bars ◽  
Tracer Particles ◽  
Bar Formation

An understanding of bedload transport processes is an essential research goal for better prediction of river morphology and morphodynamics as well as the transport and fate of sediment-bound materials in river systems. Passive tracer particles have been used widely to monitor bedload transport processes in rivers by measuring the spatiotemporal distribution of the bedload tracers. Here, we propose a numerical model for reproducing the transport of bedload tracers in river systems, more specifically, the behaviours of bedload tracers under the influence of complex river morphodynamics. A two-dimensional morphodynamic model is combined with a flux-based bedload tracer model with use of the active layer approach. The model is applied to a laboratory experiment that demonstrates the transport processes within the channel of bedload tracers supplied from the floodplain. The numerical model effectively reproduces the main features of the experiment, namely, the bedload tracers supplied from the floodplain due to bank erosion deposit onto sand bars developed within the channel. Because the sand bars cause a very long residence time of the bedload tracers within the bed, the transport speed of the tracers is slowed significantly under the influence of bar formation and channel migration.

scholarly journals Sediment Transport Processes during Barrier Island Inundation under Variations in Cross-Shore Geometry and Hydrodynamic Forcing

2019 ◽  
Vol 7 (7) ◽  
pp. 210
Author(s):  
Anita Engelstad ◽  
Gerben Ruessink ◽  
Piet Hoekstra ◽  
Maarten van der Vegt
Keyword(s):  
Sediment Transport ◽  
Morphological Changes ◽  
Barrier Island ◽  
Wave Model ◽  
Short Wave ◽  
Bedload Transport ◽  
Transport Processes ◽  
Mean Flow ◽  
Flow Transport ◽  
The Mean

Inundation of barrier islands can cause severe morphological changes, from the break-up of islands to sediment accretion. The response will depend on island geometry and hydrodynamic forcing. To explore this dependence, the non-hydrostatic wave model SWASH was used to investigate the relative importance of bedload transport processes, such as transport by mean flow, short- (0.05–1 Hz) and infragravity (0.005–0.05 Hz) waves during barrier island inundation for different island configurations and hydrodynamic conditions. The boundary conditions for the model are based on field observations on a Dutch barrier island. Model results indicate that waves dominate the sediment transport processes from outer surfzone until landwards of the island crest, either by transporting sediment directly or by providing sediment stirring for the mean flow transport. Transport by short waves was continuously landwards directed, while infragravity wave and mean flow transport was seaward or landward directed. Landward of the crest, sediment transport was mostly dominated by the mean flow. It was forced by the water level gradient, which determined the mean flow transport direction and magnitude in the inner surfzone and on the island top. Simulations suggest that short wave and mean flow transport are generally larger on steeper slopes, since wave energy dissipation is less and mean flow velocities are higher. The slope of the island top and the width of the island foremost affect the mean flow transport, while variations in inundation depth will additionally affect transport by short-wave acceleration skewness.

scholarly journals Sediment supply, grain protrusion, and bedload transport in mountain streams

2012 ◽  
Vol 39 (10) ◽  
pp. n/a-n/a ◽  
Author(s):  
E. M. Yager ◽  
J. M. Turowski ◽  
D. Rickenmann ◽  
B. W. McArdell
Keyword(s):  
Bedload Transport ◽  
Sediment Supply ◽  
Mountain Streams
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