Experimental investigation on the suppression of vortex-induced vibration of a rigid cylinder using axial slats

The study on suppression capabilities of axial slats on vortex-induced vibration (VIV) was carried out in a circulating water flume. This study aimed to find out the best combination of coverage ratio (CR) and gap ratio (GR) for the axial slats. The cylinders were set up to move in both cross-flow (CF) and in-line (IL) directions, with Reynolds number ranging from 7336 to 39346. Amplitude ratios, frequency ratios, lift and drag coefficients, trajectories and power spectral densities (PSD) were studied. A combination of CR = 0.3 and GR = 0.20 was found to be the best for axial slats to effectively suppress VIV, reducing up to 71.4 % of the CF amplitude of a bare cylinder. The best lift reduction of about 86.2 % was also found for axial slats of the same configuration. All axial slats configurations showed mean drag reduction compared to the bare cylinder, with the best reduction of 47.9 % for axial slats with CR = 0.3 and GR = 0.20. Additionally, GR was also found to have a greater influence than CR on the VIV suppression capability of axial slats.