[AM10]

Hi all,

I am simulating flow over the cylinder with LES in OpenFOAM. I am not sure about the initial boundary condition for velocity at the inlet. I ran the simulation with the fixed uniform velocity at the inlet but there is overprediction in Lift and Drag coefficient. For this case, the Turbulent intensity has been kept same as experimental data.

Simulation: Cd=1.48, Clrms=0.808
Experiment: Cd=1.14 Clrms=0.36

Please provide me some suggestion to overcome this problem

[FMDenaro]

Originally Posted by AM10

Hi all,

I am simulating flow over the cylinder with LES in OpenFOAM. I am not sure about the initial boundary condition for velocity at the inlet. I ran the simulation with the fixed uniform velocity at the inlet but there is overprediction in Lift and Drag coefficient. For this case, the Turbulent intensity has been kept same as experimental data.

Simulation: Cd=1.48, Clrms=0.808
Experiment: Cd=1.14 Clrms=0.36

Please provide me some suggestion to overcome this problem

First, you need to ensure that your grid is enough refined over the cylinder. What about dx+,dy+,dz+?
Then, the inflow in LES should be properly generate being the turbulent field 3D and time-dependent. You can read this issue in the book of Sagaut.
Alternatively, you could assume a laminar inlet with a small fluctuations superimposed and set the inlet far from the cylinder in such a way to let the flow physically correlating.