Large eddy simulation of the gas??particle turbulent wake flow

2004 ◽  
Vol 5 (1) ◽  
pp. 106-110
Author(s):  
Kun Luo ◽  
Han-hui Jin ◽  
Jian-ren Fan ◽  
Ke-fa Cen
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Wake ◽  
Wake Flow ◽  
Eddy Simulation ◽  
Large Eddy

Large Eddy Simulation of Turbulent Wake Behind a Square Cylinder With a Nearby Wall

2001 ◽  
Vol 124 (1) ◽  
pp. 81-90 ◽  
Author(s):  
Tong-Miin Liou ◽  
Shih-Hui Chen ◽  
Po-Wen Hwang
Keyword(s):  
Heat Transfer ◽  
Large Eddy Simulation ◽  
Stokes Equations ◽  
Turbulent Wake ◽  
Wake Flow ◽  
Square Cylinder ◽  
Free Standing ◽  
Mean Velocity ◽  
Eddy Simulation ◽  
Large Eddy

Computations of the time-averaged and phase-averaged fluid flow and heat transfer based on large eddy simulation (LES) are presented for turbulent flows past a square cylinder with and without a nearby wall at a fixed Reynolds number of 2.2×104. The finite-volume technique was used to solve the time-dependent filtered compressible Navier-Stokes equations with a dynamic subgrid-scale turbulence model, and the numerical fluxes were computed using alternating in time the second-order, explicit MacCormack’s and the modified Godunov’s scheme. Results show some improvements in predicting the streamwise evolutions of the long-time-averaged streamwise mean velocity and total fluctuation intensity along the centerline over those predicted by using Reynolds stress models. A better overall centerline streamwise mean velocity distribution is also predicted by the present LES than by other LES. The wall proximity effect is studied through the comparison of turbulent wake flow past one free standing cylinder and one with a nearby wall, and is illustrated by the phase-averaged spanwise vorticity components and the vortex celerity of spanwise vortices. Moreover, documentation is given on the mechanisms responsible for the augmentation of heat transfer through the spanwise and longitudinal vortices as well as periodic and random fluctuations.

Large-eddy simulation and experimental study on the turbulent wake flow characteristics of a two-bladed wind turbine

2017 ◽  
Vol 60 (12) ◽  
pp. 1861-1869 ◽  
Author(s):  
Kun Luo ◽  
RenYu Yuan ◽  
XueQing Dong ◽  
JianWen Wang ◽  
SanXia Zhang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Large Eddy Simulation ◽  
Wind Turbine ◽  
Flow Characteristics ◽  
Turbulent Wake ◽  
Wake Flow ◽  
Eddy Simulation ◽  
Large Eddy

WAVELET MULTI-RESOLUTION ANALYSIS ON LARGE-EDDY SIMULATION OF TURBURLENT FLOW BEHIND A VEHICLE EXERNAL MIRROR

2013 ◽  
Vol 11 (04) ◽  
pp. 1360007 ◽  
Author(s):  
A. RINOSHIKA ◽  
Y. ZHENG ◽  
E. SHISHIDO
Keyword(s):  
Large Eddy Simulation ◽  
Large Scale ◽  
Three Dimensional ◽  
Wake Flow ◽  
Small Scale ◽  
Three Dimensional Flow ◽  
Eddy Simulation ◽  
Multi Resolution Analysis ◽  
Large Eddy ◽  
Resolution Analysis

The three-dimensional orthogonal wavelet multi-resolution technique was applied to analyze flow structures of various scales around an externally mounted vehicle mirror. Firstly, the three-dimensional flow of mirror wake was numerically analyzed at a Reynolds number of 105 by using the large-eddy simulation (LES). Then the instantaneous velocity and vorticity were decomposed into the large-, intermediate- and relatively small-scale components by the wavelet multi-resolution technique. It was found that a three-dimensional large-scale vertical vortex dominates the mirror wake flow and makes a main contribution to vorticity concentration. Some intermediate- and relatively small-scale vortices were extracted from the LES and were clearly identifiable.

scholarly journals Large-eddy simulation of contrail evolution in the vortex phase and its interaction with atmospheric turbulence

2015 ◽  
Vol 15 (13) ◽  
pp. 7369-7389 ◽  
Author(s):  
J. Picot ◽  
R. Paoli ◽  
O. Thouron ◽  
D. Cariolle
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Flows ◽  
Atmospheric Turbulence ◽  
Three Dimensional ◽  
Vertical Direction ◽  
Ambient Air ◽  
Wake Flow ◽  
Initial Flow ◽  
Eddy Simulation ◽  
Large Eddy

Abstract. In this work, the evolution of contrails in the vortex and dissipation regimes is studied by means of fully three-dimensional large-eddy simulation (LES) coupled to a Lagrangian particle tracking method to treat the ice phase. In this paper, fine-scale atmospheric turbulence is generated and sustained by means of a stochastic forcing that mimics the properties of stably stratified turbulent flows as those occurring in the upper troposphere and lower stratosphere. The initial flow field is composed of the turbulent background flow and a wake flow obtained from separate LES of the jet regime. Atmospheric turbulence is the main driver of the wake instability and the structure of the resulting wake is sensitive to the intensity of the perturbations, primarily in the vertical direction. A stronger turbulence accelerates the onset of the instability, which results in shorter contrail descent and more effective mixing in the interior of the plume. However, the self-induced turbulence that is produced in the wake after the vortex breakup dominates over background turbulence until the end of the vortex regime and controls the mixing with ambient air. This results in mean microphysical characteristics such as ice mass and optical depth that are slightly affected by the intensity of atmospheric turbulence. However, the background humidity and temperature have a first-order effect on the survival of ice crystals and particle size distribution, which is in line with recent studies.

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