• Journal of the Society of Naval Architects of Korea
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• v.49 no.1
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• pp.93-98
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• 2012

In this study, we introduced image processing technic to measure shape variations of general bodies and applied it to the flexible yacht sail. Shape measurements of simple bodies sails were carried out and results showed that technic can be a reliable method to measure shape variations of the flexible yacht sail. The sail shape variation of 30ft sloop type yacht sail is measured on different sailing conditions. As velocity and direction of wind are increased, trailing edges in the upper part of the sail become more open than the lower part of the sail which are not changed. So it is confirmed that the shape measurement of a sail shape depending on a sailing condition is possible to use image processing scheme.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.5
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• pp.445-450
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• 2011

In order to estimate a yacht sail performance, measuring system of aerodynamic forces acting on the yacht sail is constructed and experiments of flexible model sail are carried out at the medium-size subsonic wind tunnel of Chungnam National University. Experimental results for a flexible sail are compared with experimental and numerical results of fixed shape sail. In case of a fixed shape sail, lift and drag coefficients are rarely changed at all velocity conditions. However, those of the flexible sail are decreased as the incoming velocity is increased. These are understandably resulted from shape variations due to the flexible material. Therefore aero-elastic similarity should be more carefully considered in the model test rather than other similarities.