U or V Shape: Dissipation Effects on Cylinder Flow Implicit Large-Eddy Simulation

Implicit large-eddy simulation studies of low-speed circular cylinder flows at subcritical Reynolds numbers of both 2580 and 3900 are conducted. Focus is placed on the controversial profile shape of the streamwise velocity around one diameter downstream from the cylinder. The minimum dispersion and...

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Bibliographic Details
Published in:AIAA journal 2017-02, Vol.55 (2), p.459-473
Main Authors: Chen, Haixin, Li, Zhao, Zhang, Yufei
Format: Article
Language:English
Subjects:
Aerodynamics
Bubbles
Circular cylinders
Computational fluid dynamics
Cylinders
Dispersion
Dissipation
Flow separation
Fluid dynamics
Fluid flow
Laminar flow
Large eddy simulation
Low speed
Mathematical models
Numerical analysis
Numerical dissipation
Numerical methods
Perturbation
Reynolds number
Riemann solver
Shape
Shape effects
Shear layers
Simulation
Stability
Vortex shedding
Vortices
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Summary:Implicit large-eddy simulation studies of low-speed circular cylinder flows at subcritical Reynolds numbers of both 2580 and 3900 are conducted. Focus is placed on the controversial profile shape of the streamwise velocity around one diameter downstream from the cylinder. The minimum dispersion and controllable dissipation scheme is employed for the reconstruction and the simple low-dissipation AUSM scheme is used as the Riemann solver. The combined numerical method performs well in the implicit large-eddy simulation of the separated flows. With the numerical method’s feature of controllable dissipation, the nonmonotonic effect of the numerical dissipation on the predicted length of the recirculation bubble is studied and explained. When the numerical scheme is excessively dissipative, the increasing of dissipation tends to turn the flow into laminar vortex shedding, leading to a greatly underestimated recirculation bubble and a V-shape profile. However, when the numerical dissipation is small, its mechanism of suppressing the perturbations magnified by the numerical dispersion will become important. Increasing the dissipation will then increase the predicted recirculation size by delaying the shear-layer transition and tends to show a U-shape profile result. For implicit large-eddy simulation, the dispersion should be minimized and the dissipation should be controlled to an appropriate level.
ISSN:0001-1452
1533-385X
DOI:10.2514/1.J055278