Finite Volume Study of Flow Separation Phenomena for Steady Flow over a Circular Cylinder at Low Reynolds Number

Abstract

Flow separation is one of the major distinguishing phenomena between the potential flow and actual fluid flow and circular cylinder has long been considered as the simplest form of bluff body for analyzing flow separation characteristics. Here in this article, different flow separation phenomena such as onset of separation, angular position of separation point, size of separation bubble, drag due to the separation and effect of blockage ratio on position of separation point for steady flow over a smooth circular cylinder are studied numerically using finite volume method of solving the Navier-Stokes equations at very low Reynolds number up to 50. The trends of change of these phenomena with increasing Reynolds number are expressed in form of some empirical equations and compared with results of previously published literatures. The separation starts at Reynolds number as low as 2.0 and the starting-separation angle is 146.557o from the upstream stagnation point and with increasing Reynolds number, the point of separation travels upstream while the separation bubble length increases with increasing Reynolds number. Profound effect of the blockage ratio on the location of separation point is evident in this numerical analysis.