Sailing performance analysis using CFD simulations: A study on crescent shaped wing profiles

Examensarbete för masterexamen
Naval architecture and ocean engineering (MPNAV), MSc
Nikmanesh, Melisa
The global trading market is highly dependent on the shipping that takes place today. Approximately 90% of the trades is carried out on the seas, meaning that the shipping industry have a significant impact on the environment as the current internal combustion engines causes great amount of environmental pollution. A solution to this has been to study different types of renewable propulsion types in which sails are one among others. The purpose of this study is to take an initial look at a crescent shaped sail profile and how this profile relates to the reference symmetric, NACA 0015-profile. The work of this report includes the sailing performance analysis of different parametrical changes of a crescent shaped wing profile using computational fluid dynamics, in which lift and drag coefficients are the main parameters that have been observed for 2D cases. As the validation of the software Star CCM+ was obtained for a reference profile, the crescent shaped profiles were studied. For these cases one could note much greater lift coefficients as the curvature increased and thickness was reduced. Four different crescent shapes were studied, and within these four the thinnest of them resulted in the greatest lift. Vortices occurring along the trailing edge for the cases with the best lift was observed. The occurring of vortices indicates an increase of the drag. If the mentioned increase of drag does not affect the thrust force significantly, then the crescent shaped sail profile might be the most efficient profile for generating thrust on commercial sailing vessels. Along the studied 2D observations an initial study of a 3D case has been carried out. In this case the induced drag could be stated, where the occurring of the phenomena of tip vortex causes a new addition of drag on to the sail. As of current studies the crescent shape wing profile still generates a greater lift than the reference NACA 0015-profile even after considering the induced drag.
Sail profile , CFD , crescent shape , NACA-0015 , lift coefficient , drag coefficient , 2D & 3D
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