Full-scale pressure measurements on a Sparkman and Stephens 24-foot sailing yacht

The aerodynamics of a Sparkman and Stephens 24-foot sailing yacht was investigated. Full-scale pressure measurements were performed on the mainsail and the genoa in upwind condition. Pressure taps were adopted to measure the pressures on three horizontal sections on the windward and leeward sides of the two sails. Several trims and apparent wind angles were tested. The present paper shows the pressure distributions on the sails and correlates the measured pressures with the flow pattern. In particular, leading-edge laminar separation bubble, turbulent reattachment and turbulent separation are discussed. Pressure measurements are also adopted to draw some trim guidelines.