“…Among the various geometrical forms of devices for passive suppression, helical strakes are some of the most common in both air and water flows, as can be seen in chimneys and offshore structures, such as risers and spars. Experimental studies about the effectiveness of strakes were performed by Simantiras and Willis (1999), Bearman and Brankovi´c (2004), Trim et al (2005), Brankovi´c and Bearman (2006) and Korkischko et al (2007b). Strakes can effectively suppress VIV, depending on pitch and height parameters at the expense of drag increase.…”