Numerical Simulation of Vortex Street Around the Two-Dimensional Cylinder Based on LES

Abstract

In order to study the characteristics of the Karman vortex street generated in the flow around the bluff body, this paper uses the numerical model of the large eddy simulation to numerically simulate the flow around the two-dimensional cylinder. Combined with the simulation data, this paper validates and analyzes the Karman vortex phenomenon, and studies the properties of the vortex shedding when the boundary layer is separated in the flow around the cylinder. The simulation results show that the inflow around the cylinder will produce two different characteristics of the vortex. The high velocity vortex is generated outside the boundary layer, and the small velocity vortex is generated inside the boundary layer, and the two alternately fall off to form the vortex street; When the size of the flow-through cylinder is constant, the falling vortex increases with the increase of the flow velocity, and when the flow velocity increases to a certain value, the vortex size will remain unchanged; When kept constant, the vortex is positively correlated with the size of the cylinder. The results obtained in the paper describe the Carmen vortex street generated in the flow around the two-dimensional cylinder in a relatively detailed way. Finally, this paper provides a reference for studying turbulent energy dissipation and boundary layer separation.