Vortex-induced vibration of elliptic cylinders and the suppression using mixed-convection

Transverse vortex-induced vibration (VIV) of a two-dimensional, elliptic cylinder with various aspect ratios and stiffness is studied. The elastically mounted heated, the flow direction aligned thermal-induced buoyancy force. transverse VIV can be suppressed as thermal control parameter, Richardson number (Ri), increases. Complete suppression achieved when Ri above critical value, Ric. increases ratio. For cylinders in lock-in regime, Ric optimal value since both minimum drag are achieved. A maximum reduction 50.2% was found for an ratio (AR) 2 at unsynchronized even though suppress vibration, corresponding coefficient, however, higher than that case without control. Therefore, more effective to regime. When suppressing AR 4 flexible regime using control, we observed cross-2S vortex mode, which typical 2S vortices generated near field cross centerline switch sides after few cycles.