Experimental investigation on flow-induced vibration of the flexible cylinder with attached flexible splitter plate

This experimental study investigates a flexible circular cylinder's flow-induced vibrations (FIV) with an attached flexible splitter plate. The system's dynamic response was analyzed for three splitter plate widths: 1D, 2D, and 3D, where D is the cylinder's diameter, and compared to a bare cylinder. At low reduced velocities, where the bare cylinder exhibited oscillations in its first two bending modes, the presence of the splitter plate resulted in up to a 70% reduction in oscillation amplitudes. At higher reduced velocities, the oscillation amplitude for a 1D splitter plate remained below that of the bare cylinder. In contrast, the amplitudes increased monotonically for 2D and 3D splitter plates, reaching up to three and four times the amplitudes of the bare cylinder, respectively. Multi-frequency oscillations were observed for wider splitter plates. Flow field analysis, incorporating both quantitative and qualitative methods, along with proper orthogonal decomposition of the flow field, identified two distinct FIV response types: the flexible cylinder experienced galloping type response for splitter plate widths of 1D and 2D, and vortex-induced vibration for the 3D splitter plate and the bare cylinder.