Flow-induced vibration mitigation using attached splitter-plates

Prior stationary cylinder studies have continually demonstrated the effectiveness of attached splitter-plates in reducing drag and lift coefficients of cylinders in steady uniform flow. The use of attached splitter-plates has even been reported to be able to completely eliminate vortex shedding in fixed cylinder investigations. In the present study, the proposed utility of attached splitter-plate wake-stabilisation as a passive control mechanism for vortex-induced vibration (VIV) mitigation was investigated. A range of splitter-plate ratios from I/D=O to 4 were examined over a reduced velocity interval of Ur=3 to 60. The addition of splitter-plates resulted in the desired effect of decreasing the maximum drag and lift coefficient values experienced by the bare cylinder. The amplitude response however was markedly increased at low splitter-plate lengths. A galloping type response was observed with the addition of even small splitter-plates to the cylinder. The response of the cylinders at low splitter-plate ratios appeared to be strongly influenced by vortex shedding. Key characteristics of the response such as the abrupt decrease in oscillation amplitude at higher reduced velocity aligned well with the bare cylinder vortex-induced vibration response. With increasing splitter plate ratio, there appears to be a smooth transition from pure vortex-induced vibration to a galloping type response strongly influenced by the vortex shedding at low reduced velocity and a predominantly galloping response at higher reduced velocity. Vibration mitigation was only achieved at splitter-plate lengths of I/D≤2.8 where no significant vortex-induced vibration or galloping type response was observe