Numerical Investigation of unsteady flow around a circular cylinderat different Reynolds number

In the present study, unsteady flow around a circular cylinder is simulated by ANSYS-Fluent ۱۴.۰ in laminarand turbulent flow regimes. The Finite Volume Methodwith second-order equations were applied. The couplingof pressure and velocity equations solved by PISOalgorithm. The PISO algorithm is more accurate intransient flows, also it shows vortices behind of cylinderclearer than other methods. Due to the applicability of thek-ε turbulent model, it is used in this study. In thesimulation, the effects of Reynolds number’s changes onthe formation and destruction period time of vortices anddrag and lift coefficient have investigated. The resultsshowed that by increasing the Reynolds number, the timeof formation and destruction of vortices, as well as liftcoefficient has experienced a decrease. The dragcoefficient fluctuated and the overall trend wasdecreasing. It is crystal clear that the simulation resultsare in good agreement with previous results which thenumerical error of the lift and drag coefficients were lessthan ۱۰%.

Keywords:

Lift and drag coefficients , circular cylinder , vortex , unsteady flow