On the role of turbulent large-scale streaks in generating sediment ridges

@article{Scherer2021OnTR,
  title={On the role of turbulent large-scale streaks in generating sediment ridges},
  author={Markus Dr. Scherer and Markus Uhlmann and Aman G. Kidanemariam and Michael Krayer},
  journal={Journal of Fluid Mechanics},
  year={2021},
  volume={930}
}
Abstract The role of turbulent large-scale streaks or large-scale motions in forming subaqueous sediment ridges on an initially flat sediment bed is investigated with the aid of particle resolved direct numerical simulations of open channel flow at bulk Reynolds numbers up to 9500. The regular arrangement of quasi-streamwise ridges and troughs at a characteristic spanwise spacing between 1 and 1.5 times the mean fluid height is found to be a consequence of the spanwise organisation of… 
On the existence and formation of multi-scale particle streaks in turbulent channel flows
Abstract Direct numerical simulations of particle-laden turbulent channel flows at friction Reynolds number $Re_\tau$ from $600$ to $2000$ have been performed to examine the near-wall particle

References

SHOWING 1-10 OF 135 REFERENCES
Subaqueous barchan dunes in turbulent shear flow. Part 1. Dune motion
Experiments are reported on the formation and migration of isolated dunes in a turbulent channel flow. These dunes have a very robust crescentic shape with horns pointing downstream, very similar to
Size, shape and dynamics of large-scale turbulent flow structures in a gravel-bed river
In this paper, we present a detailed investigation of the size, scale and dynamics of macro-turbulent flow structures in gravel-bed rivers. We used an array of seven electromagnetic current meters
Effects of spanwise spacing on large-scale secondary flows in rough-wall turbulent boundary layers
Large-scale secondary flows can sometimes appear in turbulent boundary layers formed over rough surfaces, creating low- and high-momentum pathways along the surface (Barros & Christensen, J. Fluid
Turbulent structures in a statistically three-dimensional boundary layer
We investigate the behaviour of large-scale coherent structures in a spanwise-heterogeneous turbulent boundary layer, using particle image velocimetry on multiple orthogonal planes. The statistical
Secondary currents and very-large-scale motions in open-channel flow over streamwise ridges
It is widely acknowledged that streamwise ridges on the bed of open-channel flows generate secondary currents (SCs). A recent discovery of meandering long streamwise counter-rotating vortices in
Turbulence and Secondary Flow over Sediment Stripes in Weakly Bimodal Bed Material
Longitudinal stripes are a common bed form in heterogeneous alluvial sediments and consist of periodic, spanwise variations in bed texture and elevation that are aligned parallel to the mean flow
Large flow structures in a turbulent open channel flow
The outer region flow structure in an open channel flow is studied by means of flow visualization and velocity measurements. The structure can be thought of as formed by large streamwise vortices
Macroturbulent structure of open-channel flow over gravel beds
The turbulent structure of open-channel flow over a mobile gravel bed was investigated in an 8 m long, 0.3 m wide, and 0.3 m deep tilting flume. A flow visualization technique was used and
Large-scale coherent flow structures in rough-bed open-channel flow observed in fluctuations of three-dimensional velocity, skin friction and bed pressure
ABSTRACT The dynamics of large-scale coherent structures (LSCS) are investigated in a rough-bed flow over the whole water column and longitudinal and transverse turbulent fluxes of momentum are
Formation of sediment patterns in channel flow: minimal unstable systems and their temporal evolution
The phenomenon of sediment pattern formation in a channel flow is numerically investigated by performing simulations which resolve all the relevant length and time scales of the problem. The
...
1
2
3
4
5
...