<正>In the present paper the mechanism involved in vortex shedding flows is investigated in detail.In the early stage of the unsteady separated flow the interaction between secondary vortices and primaryvortices is quite strong. In the later stage of the flow, corresponding to the vortex shedding the recirculatingflow region on each side of the aft body goes through such a cycle: growth-contraction-growth, the secondaryseparation occurs periodically rather than continuously. The reduction of circulation is taken into account inthree cases with different decay factors to study its influence on the prediction of main flow characteristics.Results show that to simulate vortex shedding flow it is necessary to include the reduction of circulation tobring the calculated results into good agreement with experiments. An improved discrete vortex model issuggested in which both the secondary separation and the reduction are incorporated. The processes of vortexshedding, the forces prediction and other flow characteristics are given and some discussions are made.@Chinese Academy$In the present paper the mechanism involved in vortex shedding flows is investigated in detail.In the early stage of the unsteady separated flow the interaction between secondary vortices and primaryvortices is quite strong. In the later stage of the flow, corresponding to the vortex shedding the recirculatingflow region on each side of the aft body goes through such a cycle: growth-contraction-growth, the secondaryseparation occurs periodically rather than continuously. The reduction of circulation is taken into account inthree cases with different decay factors to study its influence on the prediction of main flow characteristics.Results show that to simulate vortex shedding flow it is necessary to include the reduction of circulation tobring the calculated results into good agreement with experiments. An improved discrete vortex model issuggested in which both the secondary separation and the reduction are incorporated. The processes of vortexshedding, the forces prediction and other flow characteristics are given and some discussions are made.@of Sciences$In the present paper the mechanism involved in vortex shedding flows is investigated in detail.In the early stage of the unsteady separated flow the interaction between secondary vortices and primaryvortices is quite strong. In the later stage of the flow, corresponding to the vortex shedding the recirculatingflow region on each side of the aft body goes through such a cycle: growth-contraction-growth, the secondaryseparation occurs periodically rather than continuously. The reduction of circulation is taken into account inthree cases with different decay factors to study its influence on the prediction of main flow characteristics.Results show that to simulate vortex shedding flow it is necessary to include the reduction of circulation tobring the calculated results into good agreement with experiments. An improved discrete vortex model issuggested in which both the secondary separation and the reduction are incorporated. The processes of vortexshedding, the forces prediction and other flow characteristics are given and some discussions are made.
