Stability analysis and large-eddy simulation of rotating turbulence with organized eddies

1994 ◽  
Vol 278 ◽  
pp. 175-200 ◽  
Author(s):  
Claude Cambon ◽  
Jean-Pierre Benoit ◽  
Liang Shao ◽  
Laurent Jacquin
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Flows ◽  
Pure Shear ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Eddy Simulation ◽  
Rotating Turbulence ◽  
Special Cases ◽  
Large Eddy ◽  
The Stability

Rotation strongly affects the stability of turbulent flows in the presence of large eddies. In this paper, we examine the applicability of the classic Bradshaw-Richardson criterion to flows more general than a simple combination of rotation and pure shear. Two approaches are used. Firstly the linearized theory is applied to a class of rotating two-dimensional flows having arbitrary rates of strain and vorticity and streamfunctions that are quadratic. This class includes simple shear and elliptic flows as special cases. Secondly, we describe a large-eddy simulation of initially quasi-homogeneous three-dimensional turbulence superimposed on a periodic array of two-dimensional Taylor-Green vortices in a rotating frame.The results of both approaches indicate that, for a large structure of vorticity W and subject to rotation Ω, maximum destabilization is obtained for zero tilting vorticity (½W + 2Ω = 0) whereas stability occurs for zero absolute vorticity (2Ω = 0) These results are consistent with the Bradshaw-Richardson criterion; however the numerical results show that in other cases the Bradshaw-Richardson number $B=2\Omega(W+2\Omega)/W^2$ is not always a good indicator of the flow stability.

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.

Validation of a Three-Dimensional Large Eddy Simulation Finite Difference Method to Study Vortex Induced Vibration

2006 ◽  
Author(s):  
Paulo T. Esperanc¸a ◽  
Juan B. V. Wanderley ◽  
Carlos Levi
Keyword(s):  
Experimental Data ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Large Eddy Simulation ◽  
Difference Method ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Vortex Induced Vibration ◽  
Eddy Simulation ◽  
Large Eddy

Two-dimensional numerical simulations of Vortex Induced Vibration have been failing to duplicate accurately the corresponding experimental data. One possible explanation could be 3D effects present in the real problem that are not modeled in two-dimensional simulations. A three-dimensional finite difference method was implemented using Large Eddy Simulation (LES) technique and Message Passage Interface (MPI) and can be run in a cluster with an arbitrary number of computers. The good agreement with other numerical and experimental data obtained from the literature shows the good quality of the implemented code.

scholarly journals Cloud Cavitating Flow Over a Submerged Axisymmetric Projectile and Comparison Between Two-Dimensional RANS and Three-Dimensional Large-Eddy Simulation Methods

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Yiwei Wang ◽  
Chenguang Huang ◽  
Xin Fang ◽  
Xianian Yu ◽  
Xiaocui Wu ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Cavitating Flow ◽  
Two Dimensional ◽  
Cloud Cavitation ◽  
Cavity Collapse ◽  
Eddy Simulation ◽  
2D Simulation ◽  
Large Eddy

For the cloud cavitation around slender axisymmetric projectiles, a two-dimensional (2D) numerical method was based on the mixture approach with Singhal cavitation model and modified renormalization-group (RNG) k–ε turbulence model, and a three-dimensional (3D) method was established with large-eddy simulation (LES) and volume of fraction (VOF) approach. The commercial computational fluid dynamic (CFD) software fluent is used for the 2D simulation, and the open source code OpenFOAM is adopted for the 3D calculation. Experimental and numerical results were presented on a typical case, in which the projectile moves with a quasi-constant axial speed. Simulation results agree well with experimental results. An analysis of the evolution of cavitating flow was performed, and the related physical mechanism was discussed. Results demonstrate that shedding cavity collapse plays an important role in the generation and acceleration of re-entry jet, which is the main reason for the instability of cloud cavitation. The 2D Reynolds-Averaged Navier–Stokes (RANS) method can represent the physical phenomena effectively. The 3D LES method can give an efficient simulation on the shedding vortices, and considerable accurate shapes of shedding cavities are captured.

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
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