The geometry of the study is a straight cylindrical body (see Fig.1.). A brief description of the dimensions is provided by the table below.
Domain and Analysis type
An O-type domain was selected as the flow domain around the cylinder. The domain was 15D in the radial direction and πD in the span-wise direction (see Fig.2.). For this study a structured hexahedral mesh was created with the open source ‘BlockMesh-tool’. The grid nodes are distributed by a geometric grading in the radial direction. Further, the nodes are clustered near the stagnation point and in the wake region along the stream-wise direction. The mesh is based on a y-plus (y+) criterion of y+<1 in the radial direction. The complete details of the mesh are listed in the following table:
Mesh and Element types :
Cells in radial
Cells in circumferential
Cells in spanwise
Number of nodes
The numerical analysis performed is detailed as follows:
Tool Type : OPENFOAM®
Analysis Type : Incompressible Large Eddy Simulation
Sub-Grid-Scale Model : Smagorinsky with Cube-Root-Volume delta
Air: Dynamic viscosity (ν) =1.511−5m2s
The inlet boundary was set as a non-turbulent fixed velocity condition, while a pressure boundary condition was applied at the outlet. For the spanwise boundaries a symmetry condition was applied. The following table provides the further details.
Fixed Value: 0.59ms−1
Fixed Value: 0Pa
Fixed Value: 0.0ms−1
The numerical simulation results of mean pressure distribution and mean stream-wise velocity are compared with experimental data provided by C.Norberg  , L.Ong and J.Wallace  and L.M.Lourenco and C.Shih  . To ensure meaningful results, averaging was carried out over periods of atleast 100D/U∞ time units or about 21 vortex shedding cycles.
A comparison of the mean pressure distribution obtained with SimScale and experimental results is given in Fig.3A. The mean stream-wise velocity profile is compared with experimental data as shows by the Fig.3B.
The instantaneous vorticity component wz, and averaged streamlines in the cross-section (x-y plane) are shown by the Fig.4A and Fig.4B respectively.
A visualization of the instantaneous flow field is shown along the cross-sectional and spanwise planes provided by Fig.5A and Fig.5B.
Fig.5. Instantaneous flow field along stream-wise (left), and along span directions (right)
Norberg, ‘Effects of Reynolds number and low-intensity free stream turbulence on the flow around a circular cylinder’, Publ. No. 87 /2, Department of Applied Thermoscience and Fluid Mech., Chalmers University of Technology, Gothenburg, Sweden, 1987.
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