Flow structure around a square cylinder impacting a wall

The behavior of the flow resulting from the collision of a square cylinder with a wall without rebound at a Reynolds number of 200 was investigated computationally using the direct-forcing/fictitious domain method coupled with the finite volume method. While the emphasis of the numerical simulation was on the case in which the square cylinder collided with the wall at different impact angles, the flow generated by the impact of a circular cylinder was included for comparison. At a Reynolds number of 200, we could not observe any three-dimensional effects in the fluid flow around the square and circular cylinders resulting from the impact regardless of cylinder shape. However, the flow structure around a square cylinder after impact was more complex than that around a circular cylinder. The movement of vortex tubes around each cylinder after impact was influenced not only by the cylinder shape but also by the impact angle. The x- and y-direction drag forces on the cylinder also varied with respect to the cylinder shape and impact angle.