Stream—vorticity NS Equation ADI Scheme to Investigate Properties of Impulsively Started Translatory Flows Around the Rotational Circular Cylinder without Wall Vorticity Conditions

摘要

The propoerties of flow around a circular cylinder impulsively started into translatory and rotatory motion with rotational parameter α less than or equal to 8.0 and Reynolds number Re=100 and 200 are investigated in the present paper.The vorticity and stream function N-S equations are adopted here,with a 2nd-order spatial and temporal accuracy ADI(alternating directon implicit)scheme.Moreover the wall vorticity obtain through the principle of conservation of the total computational domain vorticity is determined by domain vorticity and stream function,therefore,through the wall vorticity iteration,the wall vorticity condition is not fixed during the time step.And the present model results indicate:(1) when α>4.0,vortex street suppression is obvious for the computational period (t<60) for all the Re numbers here studied;(2) the higher the α number for the samp Reynolds number,the slower the uper main vortex proceeds;(3) the maximum instantaneous transverse coefficient exceeds the limitation 4π.