Effect of synthetic jet on VIV and heat transfer behavior of heated sprung circular cylinder embedded in a channel

Abstract

The present study proposes a new method for mitigating the vortex-induced vibrations of a heated spring circular cylinder in a channel. According to this method, a jet flow is injected vertically from the slots embedded in the bottom wall of a channel. To suppress vortex-shedding, the slots position and the injection flow velocity are examined using comprehensive flow-structure interaction simulations. The results show that for slots close to cylinder, the cylinder vibrations drastically start to decrease from an injection velocity onwards, which is associated with a reduction in force coefficients applied to the cylinder. For these slots, the influence of the shear layer formed by flow injection gradually grows with increasing injection velocity, which brings about a perfect suppression of vortex shedding. In contrast, the jet stream farther from the cylinder has no effect on the displacement amplitude, causing only wake irregularity. In the flow injection approach, the amplitude of heat transfer coefficient decreases compared to the case without jet, and this effect starts to fade as the cylinder-slot distance increases. The minimum of overall Nusselt number occurs at a certain jet injection velocity which depends on the cylinder-slot distance and the velocity of inlet flow to the channel.