websights

Fill out the form to download

Required field
Required field
Not a valid email address
Required field
Required field

  • Set up your own cloud-native simulation in minutes.

    • Documentation

    SimScale DocumentationValidation CasesLarge Eddy Simulation: Flow Over a Cylinder

    Large Eddy Simulation: Flow Over a Cylinder

    The purpose of this numerical simulation is to validate the following parameters of the incompressible Large Eddy Simulation (LES) flow over a cylinder:

    • Pressure distribution on the cylinder surface
    • Stream-wise Velocity distribution in the wake

    The numerical simulation results of SimScale were compared with the experimental results\(^{1,2,3}\). The flow regime selected for the study is classified as sub-critical with a flow Reynolds number of \(Re\)=3900.

    Import Project into Workbench

    Geometry

    The geometry of the study is a straight cylindrical body (see Figure 1). A brief description of the dimensions is provided by the table below.

    les cylinder
    Figure 1: Geometry of the cylindrical body

    An O-type domain is selected as the flow domain around the cylinder. For cylinder diameter \(D\), the domain is 15 \(D\) in the radial direction and \(\pi D\) in the span-wise direction (see Figure 2). 

    Dimensions are given below

    DimensionValue \([m]\)
    Cylinder Diameter0.1
    Domain Thickness0.314
    Domain Diameter3
    Table 1: Cylinder and domain dimensions in meters

    Analysis Type and Mesh

    Tool Type: OpenFOAM®

    Analysis Type: Transient, Incompressible with LES Smagorinsky turbulence model.

    Mesh and Element Types:

    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 streamwise 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 Table 2:

    les cylinder
    Figure 2: Mesh used for the LES cylinder SimScale case

    Simulation Setup

    Fluid:

    • \((\nu)\) Kinematic viscosity: 0.0000151116 \(m^2/s\)
    • \((\rho)\) Density: 1 \(kg/ m^3\)

    Boundary Conditions:

    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 further details.

    Boundary SurfaceVelocityPressure
    InletFixed value of 0.59 \(m/s\)Zero gradient
    OutletInlet-outlet0 \(Pa\) Fixed value gauge pressure
    Cylinder WallFixed value of 0 \(m/s\)Zero gradient
    Front and back facesSymmetrySymmetry
    Table 2: Boundary conditions applied on the LES simulation domain

    To ensure meaningful results, it was ensured that the simulation was run for at least 3 fluid passes. The distance from the cylinder to the outlet is 1.5 \(m\). Thus, for the 0.59 \(m/s\) inlet velocity, 3 fluid passes would take approximately 8 seconds. The simulation was run for 12 seconds to achieve trustworthy results.

    Result Comparison

    The convergence plots seem to find an acceptable stability after 7 seconds. Since this is a transient simulation with eddies resolved, it was important to find the mean value of the comparing variables over the final few time steps (8-12 seconds).

    convergence plots les smagorinsky simscale
    Figure 3: Convergence plots for the LES cylinder case. The plots seem to find an acceptable stability after 7 seconds.

    The mean stream-wise velocity profile was calculated by averaging the x-component of the velocity at time steps 8, 9, 10, 11, and 12 seconds. This is compared with experimental data provided by L.Ong and J.Wallace\(^2\), and L.M.Lourenco and C.Shih\(^3\) as shown in Figure 4.

    Figure 4: Streamwise velocity profile comparison

    A comparison of the mean pressure distribution obtained with SimScale and experimental data provided by C.Norberg\(^1\) is given in Figure 5.

    Figure 5: Mean Coefficient of Pressure distribution over the cylinder surface

    A visualization of the instantaneous flow field for the velocity and pressure fields of the LES cylinder validation case is shown in Figures 6 to 10, along the cross-sectional and spanwise planes, at a time step of 9 seconds.

    Figure 6: Cross-section velocity contours
    les cylinder
    Figure 7: Cross-section velocity contours with streamlines
    Figure 8: Cross-section velocity contours with vectors
    Figure 9: Spanwise velocity contours with vectors
    les cylinder
    Figure 10: Cross-section pressure contours
    les cylinder
    Figure 11: Spanwise pressure contours with streamlines

    References

    • 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.
    • Ong and J. Wallace, ‘The velocity field of the turbulent very near wake of a circular cylinder’, Exp. Fluids, 20, 441–453, Springer Verlag, Berlin (1996).
    • L.M. Lourenco and C. Shih, ‘Characteristics of the plane turbulent near wake of a circular cylinder, a particle image velocimetry study’, Private Communication, 1993.

    Last updated: July 18th, 2025

    Contents