Reduced drag on pipes
In their paper “Passive control of VIV with drag reduction. J. Fluids and Struct. 15, pp 597-605, 2001” J.C.Owen, P.W.Bearman and A.A.Szewczyk, talk about drag reductions of between 25% and 47% on particularly shaped pipes (as opposed to straight cylinder shaped pipes). Apparently this has now also been confirmed by independent commercial research. We have mentioned this before with a reference to their European patents.
Does the added engineering costs for producing a pipe in the particular shapes overcome the benefit of the lowered drag?