Turbulent flow patterns around variably submerged boulders in mountain streams and implications to bedload transport

2014 ◽  
Author(s):  
Achilleas Georgios Tsakiris
Keyword(s):  
Turbulent Flow ◽  
Flow Patterns ◽  
Bedload Transport ◽  
Mountain Streams

Effects of a fully submerged boulder within a boulder array on the mean and turbulent flow fields: Implications to bedload transport

2012 ◽  
Vol 60 (6) ◽  
pp. 1502-1546 ◽  
Author(s):  
Athanasios N. Papanicolaou ◽  
Casey M. Kramer ◽  
Achilleas G. Tsakiris ◽  
Thorsten Stoesser ◽  
Sandeep Bomminayuni ◽  
...  
Keyword(s):  
Turbulent Flow ◽  
Flow Fields ◽  
Bedload Transport ◽  
The Mean ◽  
Boulder Array

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

Turbulent Flow over a Plane Normal Wall

1980 ◽  
Vol 22 (4) ◽  
pp. 207-211 ◽  
Author(s):  
S. M. Fraser ◽  
M. H. Siddig
Keyword(s):  
Reynolds Number ◽  
Turbulent Flow ◽  
Air Flow ◽  
Flow Patterns ◽  
Laser Doppler Anemometer ◽  
Laser Doppler ◽  
Plane Normal ◽  
Normal Wall ◽  
Side Walls

A DISA two-colour back-scatter laser Doppler anemometer was used to take measurements of mean and fluctuating velocities of an air flow of 4.6 × 104 Reynolds number in a short duct with a normal wall fixed to one side. Walls of 30 and 20 mm height were investigated and the resulting flow patterns were compared.

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).

The effect of bedload transport on mean and turbulent flow properties

Geomorphology ◽  
2000 ◽  
Vol 35 (3-4) ◽  
pp. 267-278 ◽  
Author(s):  
Patrice E. Carbonneau ◽  
Normand E. Bergeron
Keyword(s):  
Turbulent Flow ◽  
Bedload Transport ◽  
Flow Properties

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 Bedload transport measurements with impact plate geophones in two Austrian mountain streams (Fischbach and Ruetz): system calibration, grain size estimation, and environmental signal pick-up

2017 ◽  
Vol 5 (4) ◽  
pp. 669-687 ◽  
Author(s):  
Dieter Rickenmann ◽  
Bruno Fritschi
Keyword(s):  
Grain Size ◽  
Power Law ◽  
Bedload Transport ◽  
Mountain Streams ◽  
European Alps ◽  
Size Estimation ◽  
Linear Calibration ◽  
Calibration Relation ◽  
Gravel Bed Streams ◽  
Vehicle Movement

Abstract. The Swiss plate geophone system is a bedload surrogate measuring technique that has been installed in more than 20 streams, primarily in the European Alps. Here we report about calibration measurements performed in two mountain streams in Austria. The Fischbach and Ruetz gravel-bed streams are characterized by important runoff and bedload transport during the snowmelt season. A total of 31 (Fischbach) and 21 (Ruetz) direct bedload samples were obtained during a 6-year period. Using the number of geophone impulses and total transported bedload mass for each measurement to derive a calibration function results in a strong linear relation for the Fischbach, whereas there is only a poor linear calibration relation for the Ruetz measurements. Instead, using geophone impulse rates and bedload transport rates indicates that two power law relations best represent the Fischbach data, depending on transport intensity; for lower transport intensities, the same power law relation is also in reasonable agreement with the Ruetz data. These results are compared with data and findings from other field sites and flume studies. We further show that the observed coarsening of the grain size distribution with increasing bedload flux can be qualitatively reproduced from the geophone signal, when using the impulse counts along with amplitude information. Finally, we discuss implausible geophone impulse counts that were recorded during periods with smaller discharges without any bedload transport, and that are likely caused by vehicle movement very near to the measuring sites.

A Numerical Study of Turbulent Flow Characteristics of Servo-Valve Orifices

1989 ◽  
Vol 203 (2) ◽  
pp. 139-147 ◽  
Author(s):  
D C Pountney ◽  
W Weston ◽  
M R Banieghbal
Keyword(s):  
Experimental Study ◽  
Turbulent Flow ◽  
Numerical Scheme ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Flow Patterns ◽  
Servo Valve ◽  
Valve Orifice ◽  
Numerical Predictions

A numerical scheme based on the k—e turbulences model has been employed to determine turbulent flow characteristics of servo-valve orifices. Numerical predictions of flow patterns, flow coefficients and pressure variations within the valve orifice are presented and their implications for control of spool forces and cavitation effects are considered. The limitations of the model are considered and a proposal for more effective servo-valve modelling, together with a comparable experimental study, is made.

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