3D LES Prediction of Unsteady Pressure on a Circular Cylinder at Re=4.1×104

The large eddy simulation (LES) for flow around circular cylinder at Re=4.1×104 is performed in this paper. The mean and root mean square (RMS) of fluctuating pressure on circular cylinder are reasonably presented, with the mean drag coefficient, fluctuating lift coefficient and particularly the vortex-shedding Strouhal number being in good agreement with available reports. It is found that the vortex shedding is not in phases along the span wise direction, while the vortex-shedding energy is concentrated to a limited band of frequency. Statistics show that the fluctuating pressure time series at θ = 90o and θ = 270o on the opposing side of the circular share the same features, and the pressure fluctuating energy is also concentrated on the vortex-shedding frequency. The flow mechanism involved in drag and lift on cylinder is discussed according to the coherence function of the fluctuating pressure between the upper and lower cylinder surface.