Large‐Eddy Simulation of Turbulent Oscillatory Flow Over Three‐Dimensional Transient Vortex Ripple Geometries in Quasi‐Equilibrium

2020 ◽  
Vol 125 (8) ◽  
Author(s):  
Iason A. Chalmoukis ◽  
Athanassios A. Dimas ◽  
Dimokratis G. E. Grigoriadis
Keyword(s):  
Large Eddy Simulation ◽  
Oscillatory Flow ◽  
Three Dimensional ◽  
Quasi Equilibrium ◽  
Eddy Simulation ◽  
Large Eddy

scholarly journals LARGE-EDDY SIMULATION OF OSCILLATORY FLOW AND MORPHODYNAMICS OVER RIPPLES

2017 ◽  
pp. 23
Author(s):  
Georgios Leftheriotis ◽  
Athanassios Dimas
Keyword(s):  
Sediment Transport ◽  
Large Eddy Simulation ◽  
Oscillatory Flow ◽  
Three Dimensional ◽  
Immersed Boundary ◽  
Suspended Sediment Transport ◽  
Mean Flow ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Bed Form

The objective of the present study was to study the morphodynamical development of ripples in a movable bed. The methodology is based on the coupling of fluid flow, sediment transport and morphodynamics. A well-resolved large-eddy simulation (LES) is employed for the simulation of the three-dimensional turbulent oscillatory flow and the corresponding bed and suspended sediment transport over a rippled bed. The evolution of the bed form is obtained by the numerical solution of the Exner equation based on the spanwise-mean flow and sediment transport conditions. The Immersed Boundary method is implemented for the imposition of fluid and sediment boundary conditions on the moving bed surface. Results are presented for ripple creation and propagation from a quasi-flat bed, as well as results of initially sinusoidal ripples adapting to water conditions, based on the mobility number, ψ. The numerical model demonstrates phenomena of ripple creation, propagation and migration, resulting in ripple lengths in agreement with those predicted by empirical equations. It was shown that under the same hydrodynamic forcing, the bed tends to reach the same equilibrium state, regardless of the initial bed form.

Large‐Eddy Simulation of Three‐Dimensional Flow Structures Over Wave‐generated Ripples

2021 ◽  
Author(s):  
Chuang Jin ◽  
Giovanni Coco ◽  
Rafael O. Tinoco ◽  
Pallav Ranjan ◽  
Jorge San Juan ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Three Dimensional ◽  
Flow Structures ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Eddy Simulation ◽  
Large Eddy

Large Eddy Simulation of Cross Flow in Pipe Junction

2018 ◽  
Author(s):  
Jiajun Chen ◽  
Yue Sun ◽  
Hang Zhang ◽  
Dakui Feng ◽  
Zhiguo Zhang
Keyword(s):  
Large Eddy Simulation ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Cross Flow ◽  
Exciting Force ◽  
Navier Stokes ◽  
Pipe Network ◽  
Eddy Simulation ◽  
Large Eddy

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.

Large eddy simulation of stratified mixing in a three-dimensional lock-exchange system

2009 ◽  
Vol 26 (3-4) ◽  
pp. 134-155 ◽  
Author(s):  
Tamay M. Özgökmen ◽  
Traian Iliescu ◽  
Paul F. Fischer
Keyword(s):  
Large Eddy Simulation ◽  
Three Dimensional ◽  
Exchange System ◽  
Eddy Simulation ◽  
Large Eddy

scholarly journals Optimization of the Turbulence Model on Numerical Simulations of Flow Field within a Hydrocyclone

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Yan Xu ◽  
Zunce Wang ◽  
Lin Ke ◽  
Sen Li ◽  
Jinglong Zhang
Keyword(s):  
Flow Field ◽  
Large Eddy Simulation ◽  
Cross Sections ◽  
Three Dimensional ◽  
Reynolds Stress Model ◽  
Computational Grids ◽  
Test Results ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Simulation Results

Reynolds Stress Model and Large Eddy Simulation are used to respectively perform numerical simulation for the flow field of a hydrocyclone. The three-dimensional hexahedral computational grids were generated. Turbulence intensity, vorticity, and the velocity distribution of different cross sections were gained. The velocity simulation results were compared with the LDV test results, and the results indicated that Large Eddy Simulation was more close to LDV experimental data. Large Eddy Simulation was a relatively appropriate method for simulation of flow field within a hydrocyclone.

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