The role of flow angle in mixed convection and vortex-induced vibration of a thermally controlled elastic cylinder

Purpose

This study aims to investigate the effects of thermal buoyancy and flow incidence angles on mixed convection heat transfer and vortex-induced vibration (VIV) of an elastically mounted circular cylinder. The focus is on understanding how varying these parameters influences the vibration amplitudes in both the x and y directions and the overall heat transfer performance.

Design/methodology/approach

The research involves a numerical simulation of thermal fluid-structure interactions by integrating rigid-body motion equations with heat and fluid flow solvers. The cylinder operates at a lower temperature than the mainstream flow, and flow incidence angles range from 0° (opposing gravity) to 90° (perpendicular to gravity). The methodology is validated by comparing the results with established data on VIV for a cylinder vibrating in one direction under thermal buoyancy effects.

Findings

The study reveals that, without buoyancy (Ri = 0), increasing the flow angle from 0° to 90° decreases the vibration amplitude along the x-direction (A_x) while increasing it along the y-direction (A_y) across various reduced velocities (U_r). When buoyancy effects are introduced (Ri = −1), A_x peaks at specific U_r values depending on the flow angle, with significant variations observed. The maximum increase in A_x at Ri = −1 is over 15 times at U_r = 9 for a 0° angle, and A_y shows a more than 10-fold increase at U_r = 8 for a 30° angle. Additionally, adjusting the flow angle results in up to an 8% increase in the mean Nusselt number at Ri = −1.

Originality/value

This research provides novel insights into the combined effects of flow incidence angles and thermal buoyancy on VIV and heat transfer in an elastically mounted cylinder.