A collocated, iterative fractional-step method for incompressible large eddy simulation

2008 ◽  
Vol 58 (4) ◽  
pp. 355-380 ◽  
Author(s):  
Giridhar Jothiprasad ◽  
David A. Caughey
Keyword(s):  
Large Eddy Simulation ◽  
Fractional Step ◽  
Step Method ◽  
Fractional Step Method ◽  
Eddy Simulation ◽  
Large Eddy

Large Eddy Simulation of Hydraulic Characteristics of Flow around Two Parallel Circular Cylinders

2012 ◽  
Vol 468-471 ◽  
pp. 1862-1865
Author(s):  
X.J. Zhao ◽  
W.L. Wei ◽  
Xi Wang ◽  
Ming Qin Liu
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Flows ◽  
Circular Cylinders ◽  
Hydraulic Characteristics ◽  
Step Method ◽  
Fractional Step Method ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Engineering Problems ◽  
Total Velocity

large eddy simulation cooperated with a physical fractional-step method was applied to simulate steady flow around two parallel circular cylinders. The total velocity vectors, pressure contours and vorticity magnitude are obtained. The modeling results conform to physical law, and show that the large eddy simulation theory has powerful capacity in simulation of microstructures of turbulent flows, and can be widely applied to the solution of real engineering problems.

Large Eddy Simulation of Gas-Liquid Two-Phase Flow for a Nested Type Fixed-Cone Valve

2012 ◽  
Vol 170-173 ◽  
pp. 2458-2463
Author(s):  
Y.L. Liu ◽  
B. Lv ◽  
W.L. Wei
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Flows ◽  
Free Fluid ◽  
Step Method ◽  
Fractional Step Method ◽  
Two Phase ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Volume Method ◽  
Free Fluid Surface

large eddy simulation cooperated with a physical fractional-step method is applied to simulate steady flow around a nested type fixed-cone valve; and the equations are solved with the finite volume method. The free fluid surface is simulated by the VOF method. The pressure contours and vorticity magnitude are obtained. The modeling results conform to physical law, and show that the large eddy simulation theory has powerful capacity in simulation of microstructures of turbulent flows, and the function of the nested type fixed-cone valve for energy dissipating is good.

Large Eddy Simulation of Flow Past a Square Cylinder: Comparison of Different Subgrid Scale Models

1999 ◽  
Vol 122 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Ahmad Sohankar ◽  
L. Davidson ◽  
C. Norberg
Keyword(s):  
Large Eddy Simulation ◽  
Equation Model ◽  
Subgrid Scale ◽  
Step Method ◽  
Fractional Step Method ◽  
Time Step ◽  
Eddy Simulation ◽  
Flow Past ◽  
Scale Models ◽  
Large Eddy

Large eddy simulation of flow past a rigid prism of a square cross section with one side facing the oncoming flow at Re=2.2×104 is performed. An incompressible code is used employing an implicit fractional step method finite volume with second-order accuracy in space and time. Three different subgrid scale models: the Smagorinsky, the standard dynamic, and a dynamic one-equation model, are applied. The influence of finer grid, shorter time step, and larger computational spanwise dimension is investigated. Some global quantities, such as the Strouhal number and the mean and rms values of lift and drag, are computed. A scheme for correcting the global results for blockage effects is presented. By comparison with experiments, the results produced by the dynamic one-equation one give better agreement with experiments than the other two subgrid models. [S0098-2202(00)01001-4]

Application of Large Eddy Simulation to an Oscillating Flow Past a Circular Cylinder

1997 ◽  
Vol 119 (3) ◽  
pp. 519-525 ◽  
Author(s):  
Xiyun Lu ◽  
Charles Dalton ◽  
Jianfeng Zhang
Keyword(s):  
Circular Cylinder ◽  
Large Eddy Simulation ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Scale Model ◽  
Oscillating Flows ◽  
Step Method ◽  
Fractional Step Method ◽  
Eddy Simulation ◽  
Large Eddy

Three-dimensional sinusoidally oscillating flows around a circular cylinder are investigated by using a viscous flow method (VFM) and a large eddy simulation (LES). A second-order accurate in time fractional step method and a combined finite-difference/spectral approximation are employed to solve the filtered incompressible Navier-Stokes equations. To demonstrate the viability and accuracy of the method, we calculate two cases of steady approach, flows at Reynolds numbers Re = 100 using VFM and Re = 104 using LES. For sinusoidally oscillating flows at β = 1035, the flow is 2D for KC< 0.5, 3D for 0.5 < KC < 2, and turbulent for KC > 2. For KC = 0.5, 0.8 and 1, the flow is calculated using VFM. For KC = 2, 3, 4, 5, 8 and 10, we have simulated the flow using LES with the Smagorinsky subgrid scale model. The drag and inertia coefficients are calculated from the in-line force acting on the cylinder and are in very good agreement with experimental data.

Application of Large Eddy Simulation to Flow Past a Circular Cylinder

1997 ◽  
Vol 119 (4) ◽  
pp. 219-225 ◽  
Author(s):  
X. Lu ◽  
C. Dalton ◽  
J. Zhang
Keyword(s):  
Circular Cylinder ◽  
Large Eddy Simulation ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Scale Model ◽  
Step Method ◽  
Fractional Step Method ◽  
Eddy Simulation ◽  
Large Eddy

A steady approach flow around a circular cylinder is investigated by using a large eddy simulation (LES) with the Smagorinsky subgrid-scale model. A second-order accurate in time fractional-step method and a combined finite-difference/spectral approximation are employed to solve the filtered three-dimensional incompressible Navier-Stokes equations. To demonstrate the viability and accuracy of the method, we present results at Reynolds numbers of 100, 3 × 103, 2 × 104, and 4.42 × 104. At Re = 100, the physical flow is two-dimensional and the calculation is done without use of the LES method. For the higher values of Re, the flow in the wake is three-dimensional and turbulent and the LES method is necessary to describe the flow accurately. Calculated values of lift and drag coefficients and Strouhal number are in good agreement with the experimentally determined values at all of the Reynolds numbers for which calculation was done.

Large Eddy Simulations of a Hydrocyclone

2002 ◽  
Author(s):  
Francisco Jose´ de Souza ◽  
Aristeu Silveira Neto
Keyword(s):  
Turbulence Models ◽  
Fluid Flows ◽  
Scale Model ◽  
Staggered Grid ◽  
Subgrid Scale ◽  
Step Method ◽  
Fractional Step Method ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Subgrid Scale Modeling

Subgrid-scale modeling, which characterizes Large Eddy Simulation (LES), has been used to predict the behavior of a water-fed hydrocyclone operating without an air core. The governing equations were solved by a fractional step method on a staggered grid. The Smagorinsky subgrid-scale model was employed to account for turbulent effects. Numerical results actually capture the main features of the flow pattern and agree reasonably well with experiments, suggesting that LES represents an interesting alternative to classical turbulence models when applied to the numerical solution of fluid flows within hydrocyclones.

Prediction of Unsteady Loading on a Circular Cylinder in High Reynolds Number Flows Using Large Eddy Simulation

2005 ◽  
Author(s):  
Sung-Eun Kim ◽  
L. Srinivasa Mohan
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Turbulent Viscosity ◽  
Reynolds Numbers ◽  
Unstructured Meshes ◽  
Navier Stokes ◽  
Step Method ◽  
Fractional Step Method ◽  
Eddy Simulation ◽  
Large Eddy

Large eddy simulations were carried out for the flow around a hydrodynamically smooth, fixed circular cylinder at two Reynolds numbers, one at a subcritical Reynolds number (Re = 1.4 × 105) and the other at a supercritical Reynolds number (Re = 1.0 × 106). The computations were made using a parallelized finite-volume Navier-Stokes solver based on a multidimensional linear reconstruction scheme that allows use of unstructured meshes. Central differencing was used for discretization of both convection and diffusion terms. Time-advancement scheme, based on an implicit, non-iterative fractional-step method, was adopted in conjunction with a three-level, backward second-order temporal discretization. Subgrid-scale turbulent viscosity was modeled by a dynamic Smagorinsky model adapted to arbitrary unstructured meshes with the aid of a test-filter applicable to arbitrary unstructured meshes. The present LES results closely reproduced the flow features observed in experiments at both Reynolds numbers. The time-averaged mean drag coefficient, root-mean-square force coefficients and the frequency content of fluctuating forces (vortex-shedding frequency) are predicted with a commendable accuracy.

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