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 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…
6 Citations
Open-channel flow over evolving subaqueous ripples
- PhysicsJournal of Fluid Mechanics
- 2022
Abstract We have numerically investigated the turbulent flow and sediment grain motion in an open-channel flow configuration over a subaqueous sediment bed featuring two-dimensional transverse…
On the existence and formation of multi-scale particle streaks in turbulent channel flows
- PhysicsJournal of Fluid Mechanics
- 2022
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…
Role of the hierarchy of coherent structures in the transport of heavy small particles in turbulent channel flow
- PhysicsJournal of Fluid Mechanics
- 2022
Abstract To investigate the transport of heavy small particles (inertial particles) in high-Reynolds- number wall turbulence, we conduct direct numerical simulations of inertial particles in…
Causality between fluid motions and bathymetric features
- PhysicsJournal of Fluid Mechanics
- 2022
Abstract Can morphodynamic problems be solved using a first-principles approach in multiphase fluid mechanics? This is the holy grail for many sediment transport researchers but has yet to be…
Bottom wall shear stress fluctuations in shallow-water Langmuir turbulence
- Engineering, PhysicsJournal of Fluid Mechanics
- 2022
Abstract In neutrally stratified shallow water, full-depth Langmuir cells (LCs) can interact with the turbulent benthic boundary layer and, thus, influence bottom wall shear stresses. In this paper…
The effect of spanwise heterogeneous roughness on mixed convection in turbulent channels
- Physics
- 2022
must not spill onto p.2 ar X iv :2 20 3. 09 81 7v 1 [ ph ys ic s. fl udy n] 1 8 M ar 2 02 2
References
SHOWING 1-10 OF 135 REFERENCES
Subaqueous barchan dunes in turbulent shear flow. Part 1. Dune motion
- GeologyJournal of Fluid Mechanics
- 2011
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…
Longitudinal streaks
- GeologyJournal of Fluid Mechanics
- 1995
A commonly observed bedform in wide erodible-bed channels consists of rows of streaks or stripes parallel to the flow. These stripes can be manifested in terms of transverse variation of bed…
Size, shape and dynamics of large-scale turbulent flow structures in a gravel-bed river
- PhysicsJournal of Fluid Mechanics
- 2004
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
- PhysicsJournal of Fluid Mechanics
- 2015
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
- Physics, Environmental ScienceJournal of Fluid Mechanics
- 2018
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
- Physics, Environmental ScienceJournal of Fluid Mechanics
- 2020
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
- Engineering
- 1999
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
- Physics, Environmental Science
- 1999
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…
Turbulence-driven secondary flows and formation of sand ridges
- PhysicsJournal of Fluid Mechanics
- 1993
The mechanism of generation of sand ridges, longitudinal stripes observed both in natural rivers and in the laboratory, is investigated with the aim of showing that the initiation mechanism is…
Large-scale coherent flow structures in rough-bed open-channel flow observed in fluctuations of three-dimensional velocity, skin friction and bed pressure
- Physics
- 2018
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…