Detailed Investigation of Detached-Eddy Simulation for the Flow Past a Circular Cylinder at Re=3900

2012 ◽  
Vol 232 ◽  
pp. 471-476 ◽  
Author(s):  
Rui Zhao ◽  
Chao Yan
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Flow Structures ◽  
Detached Eddy Simulation ◽  
Eddy Simulation ◽  
Flow Past ◽  
Large Eddy ◽  
Mesh Resolution ◽  
Physical Phenomena

The flow past a circular cylinder at a subcritical Reynolds number 3900 was simulated by the method of detached-eddy simulation (DES). The objective of this present work is not to investigate the physical phenomena of the flow but to study modeling as well as numerical aspects which influence the quality of DES solutions in detail. Firstly, four typical spanwise lengths are chosen and the results are systematically compared. The trend of DES results along the span increment is different from previous large-eddy simulation (LES) investigation. A wider spanwise length does not necessary improve the results. Then, the influence of mesh resolution is studied and found that both too coarse and over refined grids will deteriorate the performance of DES. Finally, different orders of numerical schemes are applied in the inviscid fluxes and the viscous terms. The discrepancies among different schemes are found tiny. However, the instantaneous flow structures produced by 5th order WENO with 4th order central differencing scheme are more abundant than the others. That is, for the time-averaged quantities, the second-order accurate schemes are effective enough, whereas the higher-order accurate methods are needed to resolve the transient characteristics of the flow.

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.

Partially Averaged Navier–Stokes (PANS) Method for Turbulence Simulations: Flow Past a Circular Cylinder

2010 ◽  
Vol 132 (12) ◽  
Author(s):  
Sunil Lakshmipathy ◽  
Sharath S. Girimaji
Keyword(s):  
Circular Cylinder ◽  
Navier Stokes ◽  
Length Scale ◽  
Detached Eddy Simulation ◽  
Mean Flow ◽  
Closure Model ◽  
Variable Resolution ◽  
Eddy Simulation ◽  
Flow Past ◽  
High Reynolds

The objective of this study is to evaluate the capability of the partially averaged Navier–Stokes (PANS) method in a moderately high Reynolds number (ReD 1.4×105) turbulent flow past a circular cylinder. PANS is a bridging closure model purported for use at any level of resolution ranging from Reynolds-averaged Navier–Stokes to direct numerical simulations. The closure model is sensitive to the length-scale cut-off via the ratios of unresolved-to-total kinetic energy (fk) and unresolved-to-total dissipation (fε). Several simulations are performed to study the effect of the cut-off length-scale on computed closure model results. The results from various resolutions are compared against experimental data, large eddy simulation, and detached eddy simulation solutions. The quantities examined include coefficient of drag (Cd), Strouhal number (St), and coefficient of pressure distribution (Cp) along with the mean flow statistics and flow structures. Based on the computed results for flow past circular cylinder presented in this paper and analytical attributes of the closure model, it is reasonable to conclude that the PANS bridging method is a theoretically sound and computationally viable variable resolution approach for practical flow computations.

scholarly journals EFFECT OF THE SPANWISE DISCRETISATION ON TURBULENT FLOW PAST A CIRCULAR CYLINDER

2021 ◽  
Vol 158 (A1) ◽  
Author(s):  
S Kim ◽  
P A Wilson ◽  
Z Chen
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Flow Field ◽  
Large Eddy Simulation ◽  
Turbulent Flow ◽  
Three Dimensional ◽  
Scale Model ◽  
Spatial Density ◽  
Eddy Simulation ◽  
Large Eddy

The effect of the spanwise discretisation on numerical calculations of the turbulent flow around a circular cylinder is systematically assessed at a subcritical Reynolds number of 10000 in the frame of three-dimensional large-eddy simulation. The eddy-viscosity k-equation subgrid scale model is implemented to evaluate unsteady turbulent flow field. Large-eddy simulation is known to be a reliable method to resolve such a challenging flow field, however, the high computational efforts restrict to low Reynolds number flow or two-dimensional calculations. Therefore, minimum spatial density in the spanwise direction or cylinder axis direction needs to be carefully evaluated in order to reduce high computational resources. In the present study, the influence of the spanwise resolutions to satisfactorily represent three- dimensional complex flow features is discussed in detail and minimum spatial density for high Reynolds flow is suggested.

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