A numerical study of particle motion and two-phase interaction in aeolian sand transport using a coupled large eddy simulation - discrete element method

Sedimentology ◽  
2013 ◽  
Vol 61 (2) ◽  
pp. 319-332 ◽  
Author(s):  
Zhiqiang Li ◽  
Yuan Wang ◽  
Yang Zhang
Author(s):  
Théa Lancien ◽  
Kevin Prieur ◽  
Daniel Durox ◽  
Sébastien Candel ◽  
Ronan Vicquelin

A combined experimental and numerical study of light-round, defined as the flame propagation from burner to burner in an annular combustor, under perfectly premixed conditions has previously demonstrated the ability of large-eddy simulation (LES) to predict such ignition processes in a complex geometry using massively parallel computations. The present investigation aims at developing light-round simulations in a configuration closer to real applications by considering liquid n-heptane injection. The large-eddy simulation of the ignition sequence of a laboratory scale annular combustion chamber comprising sixteen swirled two-phase injectors is carried out with a mono-disperse Eulerian approach for the description of the liquid phase. The objective is to assess this modeling approach to describe the two-phase reactive flow during the ignition process. The simulation results are compared in terms of flame structure and light-round duration to the corresponding experimental images of the flame front recorded by a high-speed intensified CCD camera. The dynamics of the flow is also analyzed to identify and characterize mechanisms controlling flame propagation during the light-round process.


2015 ◽  
Vol 42 (6) ◽  
pp. 2063-2070 ◽  
Author(s):  
Thomas Pähtz ◽  
Amir Omeradžić ◽  
Marcus V. Carneiro ◽  
Nuno A. M. Araújo ◽  
Hans J. Herrmann

Atmosphere ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 448
Author(s):  
Yang Zhang ◽  
Changsong Wu ◽  
Xiaosi Zhou ◽  
Yuanming Hu ◽  
Yuan Wang ◽  
...  

A numerical investigation of aeolian sand particle flow in atmospheric boundary layer is performed with a Eulerian–Eulerian granular pseudofluid model. In this model, the air turbulence is modelled with a large eddy simulation, and a kinetic–frictional constitutive model incorporating frictional stress and the kinetic theory of granular flow is applied to describe the interparticle movement. The simulated profiles of streamwise sand velocity and sand mass flux agree well with the reported experiments. The quantitative discrepancy between them occurs near the sand bed surface, which is due to the difference in sand sample, but also highlights the potential of the present model in addressing near-surface mass transport. The simulated profiles of turbulent root mean square (RMS) particle velocity suggest that the interparticle collision mainly account for the fluctuation of sand particle movement.


2012 ◽  
Vol 170-173 ◽  
pp. 2703-2707
Author(s):  
W.L. Wei ◽  
X.J. Zhao ◽  
Y.L. Liu ◽  
X.F. Yang

This paper is concerned with the numerical study of gas–liquid flow in bubble columns by large eddy simulations (LES). The Euler–Euler approach is used to describe the equations of motion of the two-phase flow. The mean velocities and the fluctuating velocities are obtained. It is found that, when the drag, lift and virtual mass forces are used, the computed results in agreement with experimental transient behavior can be captured.


Author(s):  
V. A. SABELNIKOV ◽  
◽  
V. V. VLASENKO ◽  
S. BAKHNE ◽  
S. S. MOLEV ◽  
...  

Gasdynamics of detonation waves was widely studied within last hundred years - analytically, experimentally, and numerically. The majority of classical studies of the XX century were concentrated on inviscid aspects of detonation structure and propagation. There was a widespread opinion that detonation is such a fast phenomenon that viscous e¨ects should have insigni¦cant in§uence on its propagation. When the era of calculations based on the Reynolds-averaged Navier- Stokes (RANS) and large eddy simulation approaches came into effect, researchers pounced on practical problems with complex geometry and with the interaction of many physical effects. There is only a limited number of works studying the in§uence of viscosity on detonation propagation in supersonic §ows in ducts (i. e., in the presence of boundary layers).


Author(s):  
Kin’ya Takahashi ◽  
Masataka Miyamoto ◽  
Yasunori Ito ◽  
Toshiya Takami ◽  
Taizo Kobayashi ◽  
...  

The acoustic mechanisms of 2D and 3D edge tones and a 2D small air-reed instrument have been studied numerically with compressible Large Eddy Simulation (LES). Sound frequencies of the 2D and 3D edge tones obtained numerically change with the jet velocity well following Brown’s semi-empirical equation, while that of the 2D air-reed instrument behaves in a different manner and obeys the semi-empirical theory, so called Cremer-Ising-Coltman theory. We have also calculated aerodynamic sound sources for the 2D edge tone and the 2D air-reed instrument relying on Ligthhill’s acoustic analogy and have discussed similarities and differences between them. The sound source of the air-reed instrument is more localized around the open mouth compared with that of the edge tone due to the effect of the strong sound field excited in the resonator.


2018 ◽  
Author(s):  
Jiajun Chen ◽  
Yue Sun ◽  
Hang Zhang ◽  
Dakui Feng ◽  
Zhiguo Zhang

Mixing in pipe junctions can play an important role in exciting force and distribution of flow in pipe network. This paper investigated the cross pipe junction and proposed an improved plan, Y-shaped pipe junction. The numerical study of a three-dimensional pipe junction was performed for calculation and improved understanding of flow feature in pipe. The filtered Navier–Stokes equations were used to perform the large-eddy simulation of the unsteady incompressible flow in pipe. From the analysis of these results, it clearly appears that the vortex strength and velocity non-uniformity of centerline, can be reduced by Y-shaped junction. The Y-shaped junction not only has better flow characteristic, but also reduces head loss and exciting force. The results of the three-dimensional improvement analysis of junction can be used in the design of pipe network for industry.


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