Milgram 



M^ Heeling moment about the midspan of a sail 



p Pressure 



Ap Pressure difference 



R^ Reynolds number based on chord length 



Rg Reynolds number based on momentum thickness 



u Apparent wind 



Uq Apparent wind at midspan 



u' , V ' , w' Perturbation velocity components 



X, y, z Coordinate axes moving with vessel; x is in the apparent wind 

 direction or in the plane containing the three corners of a sail, 

 z is positive in the direction to which the wind is blowing, y 

 is positive upward 



X Forward force — in the direction of the course of a vessel 



Y Side force 



a. Induced angle 



J3 Angle between a vessel's course and the true wind 



7 Vortex sheet strength 



r Circulation 



7] Dummy linear variable 



$ Heel angle; velocity potential 



</-, "A', $ Dummy angular variables 



P Density of air 



BIBLIOGRAPHY 



Abbott, I.A., and Von Doenhoff, A.E., 1959. Theory of Wing Sections. 

 New York: Dover Publications 



Ashley, H., and Landahl, M., 1965. Aerodynamics of Wings and Bodies. 

 Reading, Massachusetts: Addison Wesley Publishing Co., Inc. 



1426 



