Numerical Investigation of Flow Around 2D Modified Circular Cylinders at the Low Reynolds Number

Flow characteristics around a circular cylinder are great important in ubiquitous engineering applications. When Reynolds number surpasses a particular value, fluid flow around the cylinder appears alternative vortex shedding which changes flow characteristics including varying lift force and base pressure on the cylinder. Vortex shedding characteristics are shown to be affected by adding a horizontal or vertical slit to the original circular cylinder in the literature. In the current work, we assessed the influence of normal slit location −0.25, −0.1, 0, 0.1, 0.25; and influence of with and without rear concave shape on flow characteristics by performing two-dimensional simulations at the Reynolds number 200 using ANSYS Fluent software. Results show that both modified circular cylinder configurations with a normal slit or with a rear concave shape have significant effects on vortex shedding enhancement. The underlying mechanism of vortex shedding enhancement in the case of a normal slit is found to be the blowing/suction mechanism which has the greatest effect when the slit crosses the cylinder center. The rear concave surface is also helpful in generating stronger and faster vortex shedding.