Bulletin of the JSME Vol.10, No.2, 2015 Journal of Fluid Science and Technology Performance of wing sail with multi element by two- dimensional wind tunnel investigations Hiroyuki FURUKAWA*, Alexander W. BLAKELEY **, Richard G.J. FLAY ** and Peter J. RICHARDS ** * Department of Mechanical Engineering, Meijo University 1-501 Shiogamaguchi, Tenpaku-ku, Nagoya 468-8502, Japan E-mail:
[email protected] **Department of Mechanical Engineering, University of Auckland 314-390 Khyber Pass Road, Auckland, New Zealand Received 30 April 2015 Abstract Following the 33rd America's Cup which featured a trimaran versus a catamaran, and the recent 34th America's Cup in 2013 featuring AC72 catamarans with multi-element wing sail yachts sailing at unprecedented speeds, interest in wing sail technology has increased substantially. Unfortunately there is currently very little open peer- reviewed literature available witha focus on multi-element wing design for yachts. The limited available literature focuses primarily on the structures of wings and their control, rather than on the aerodynamic design. While there is substantial available literature on the aerodynamic properties of aircraft wings, the differences in the flow domains between aeroplanes and yachts is significant. A yacht sail will operate in a Reynolds number range of 0.2 to 8 million while aircraft operate regularly in excess of 10 million. Furthermore, yachts operate in the turbulent atmospheric boundary layer and require high maximum lift coefficients at many apparent wind angles, and minimising drag is not so critical. This paper reviews the literature onwing sail design for high performance yachts and discusses the results of wind tunnel testing at the Yacht Research Unit at the University of Auckland.