TY - GEN
T1 - The interaction of downwind sails
AU - Lasher, William C.
PY - 2006
Y1 - 2006
N2 - When a sailboat is sailing in the general direction of the wind, it is known as downwind sailing. Under these conditions boats generally carry two sails - a mainsail and a spinnaker. The flow over these sails is complicated and poorly understood. An issue of importance to sailors is how the adjustment of one sail affects the aerodynamics of the other sail and the total driving force. In the present work a CFD analysis was performed on two different sailboat rigs, with an emphasis on the interactions between the main and spinnaker. The results show that the optimum angle of attack of the mainsail is generally 60° to 70°, depending on the direction of the wind relative to the boat. The correct setting for a mainsail has been a point of debate amongst sailors, and the present analysis supports the theory of easing the mainsail until it luffs (or flaps), then pulling it in. A surprising result is that when the wind is directly behind the boat, the mainsail should not be set to maximize projected area, but eased out past 90°. This is difficult to accomplish in practice due to restrictions of the rig, but raise some interesting questions.
AB - When a sailboat is sailing in the general direction of the wind, it is known as downwind sailing. Under these conditions boats generally carry two sails - a mainsail and a spinnaker. The flow over these sails is complicated and poorly understood. An issue of importance to sailors is how the adjustment of one sail affects the aerodynamics of the other sail and the total driving force. In the present work a CFD analysis was performed on two different sailboat rigs, with an emphasis on the interactions between the main and spinnaker. The results show that the optimum angle of attack of the mainsail is generally 60° to 70°, depending on the direction of the wind relative to the boat. The correct setting for a mainsail has been a point of debate amongst sailors, and the present analysis supports the theory of easing the mainsail until it luffs (or flaps), then pulling it in. A surprising result is that when the wind is directly behind the boat, the mainsail should not be set to maximize projected area, but eased out past 90°. This is difficult to accomplish in practice due to restrictions of the rig, but raise some interesting questions.
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U2 - 10.1115/fedsm2006-98173
DO - 10.1115/fedsm2006-98173
M3 - Conference contribution
AN - SCOPUS:33847075025
SN - 0791847500
SN - 9780791847503
T3 - Proceedings of ASME Fluids Engineering Division Summer Meeting 2006, FEDSM2006
SP - 263
EP - 272
BT - Proceedings of ASME Fluids Engineering Division Summer Meeting 2006, FEDSM2006
PB - American Society of Mechanical Engineers
T2 - 2006 ASME Joint U.S.- European Fluids Engineering Division Summer Meeting, FEDSM2006
Y2 - 17 July 2006 through 20 July 2006
ER -