A three-dimensional inverse sail design method
2010 (English)In: Transactions of the Royal Institution of Naval Architects Part B: International Journal of Small Craft Technology, ISSN 1740-0694, Vol. 152, no 2, p. B107-B114Article in journal (Refereed) Published
Abstract [en]
Today sail shapes are usually designed using analysis methods i.e. based on experience the designer specifies a certain sail shape and then proceeds to determine the aerodynamic characteristics of this sail. Finding optimum sail shapes using such a method can involve a lot of trial and error. A new approach in sail design is proposed in this paper, where an inverse method is considered. The inverse method involves specifying the aerodynamic characteristics, and working backwards to obtain the corresponding sail shape to produce those characteristics. The paper investigates a single sail in an upwind condition. Because the solution of the inverse process is not unique, some variables have to be fixed. The sail shape is defined by three parameters: the planform, the camber, and the twist. In the present work, the planform is assumed to be defined by the class-rules of the yacht and is thus known. The sail designer has to specify one of the two possible trims: the twist or the camber. Then the theory, described in the paper, shows that there is a unique solution of the inverse process. Thus two cases are considered. The first involves a fixed twist and planform. There, the code generates the camber of the sail which will produce a given pressure distribution. The second case considers a fixed camber and planform. Here the code trims the sail twist to match the desired pressure distribution. Validation tests have been performed and results are presented. To validate the current approach, the pressure map was first computed from a specified shape. Then the resulting pressure distribution was employed as an input to the inverse method. The shape of the sail obtained with the inverse method is compared to the shape initially used in the analysis. The agreement is good in both inverse computations.
Place, publisher, year, edition, pages
2010. Vol. 152, no 2, p. B107-B114
Keywords [en]
Aerodynamic characteristics, Analysis method, Design method, Inverse computation, Inverse methods, Inverse process, New approaches, Planform, Three parameters, Trial and error, Validation test, Aerodynamics, Cambers, Design, Inverse problems, Pressure distribution, Ships, Planforms
National Category
Mechanical Engineering
Identifiers
URN: urn:nbn:se:ri:diva-71815DOI: 10.3940/rina.ijsct.2010.b2.104tnScopus ID: 2-s2.0-79951732685OAI: oai:DiVA.org:ri-71815DiVA, id: diva2:1838082
2024-02-152024-02-152024-02-15Bibliographically approved