Vortex shedding from a square cylinder in presence of a moving wall

Abstract

SUMMARYA numerical study on the ow past a square cylinder placed parallel to a wall, which is moving at the speed of the far ÿeld has been made. Flow has been investigated in the laminar Reynolds number (based on the cylinder length) range. We have studied the ow ÿeld for di erent values of the cylinder to wall separation length. The governing unsteady Navier-Stokes equations are discretized through the ÿnite volume method on a staggered grid system. A SIMPLE type of algorithm has been used to compute the discretized equations iteratively. A shear layer of negative vortex generates along the surface of the wall, which in uences the vortex shedding behind the cylinder. The ow-ÿeld is distinct from the ow in presence of a stationary wall. An alternate vortex shedding occurs for all values of gap height in the unsteady regime of the ow. The strong positive vortex pushes the negative vortex upwards in the wake. The gap ow in the undersurface of the cylinder is strong and the velocity proÿle overshoots. The cylinder experiences a downward force for certain values of the Reynolds number and gap height. The drag and lift are higher at lower values of the Reynolds number.

Vortex shedding from a circular cylinder near a moving wall

“…They found that the kinematic condition of the wall does not affect the gross flow characteristics, such as the Strouhal number and lift force, but does significantly alter the trajectory of the vortices behind the cylinder. Bhattacharyya and Maiti (2005) simulated the two-dimensional laminar flow past a square cylinder placed parallel to a moving wall; they found that vortex shedding occurs even at the very small gap ratio of G/D ¼ 0.1.…”

Lattice Boltzmann simulation of flow past a circular cylinder near a moving wall

“…Kumarasamy and Barlow [9] simulated the flow over a half cylinder close to a moving wall and compared the results with those of stationary wall. Bhattacharyya and Maiti [10] simulated the two-dimensional laminar flow past a square cylinder placed parallel to a moving wall. They found that vortex shedding occurs even at a very small gap ratio of G=D D 0.1.…”