“…For cylinders in wind, an effective helical strake geometry has three starts (each spaced 120° apart around the cylinder circumference) (Zhou et al, 2011;Sui et al, 2016). Moreover, it has been proved that the triple-start helical strake system has worked well for many years in water and used popular for VIV suppression of marine slender structures (Trim et al, 2005;Quen et al, 2014a;Gao et al, 2016). In addition, it has also been observed that with the increasing strakes coverage, the VIV suppression efficiency of a flexible cylinder increased gradually to the maximum at 100% coverage (Frank et al, 2004;Trim et al, 2005;Vandiver et al, 2006;Gao et al, 2016).…”