Marzie Babaie Rabiee

The vortex-shedding phenomenon leads to a self-sustained vibration named Vortex-Induced Vibration (VIV), an important mass transfer enhancement method. This work studies the VIV effects of two circular cylinders inside a channel in a tandem arrangement on the mixing performance. A comprehensive study is conducted on different modes of cylinder vibrations, i.e., both cylinders vibrate, one cylinder vibrates, another cylinder is stationary, and both cylinders are stationary. The finite volume method is applied to solve the fluid flow equations, and the cylinders’ vibration is modeled as a mass-spring-damping system. At low ranges of the reduced velocity, the vibration’s amplitude of the cylinder is significant, and the mixing index reaches its highest values. For the case in which the distance between two cylinders is four times their diameter, the best mixing performance is related to two vibrating cylinders. In this mode, the mixing index increased up to 35% and 78% with respect to two stationary cylinders and a single stationary cylinder, respectively. Also, the investigation shows that increasing the distance between the cylinders improves the mixing process. For cylinders’ distances of 4.5 and 5, the mixing index reaches 98% and up at the channel outlet.