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Sail Plan Parametric CAD Model for an A-Class Catamaran Numerical Optimization Procedure Using Open Source Tools

  • Ubaldo Cella
  • Filippo Cucinotta
  • Felice Sfravara
Chapter
Part of the Lecture Notes in Mechanical Engineering book series (LNME)

Abstract

A geometric tool for a catamarans sail plan and appendages optimization procedure is descripted. The method integrates a parametric CAD model, an automatic computational domain generator and a Velocity Prediction Program (VPP) based on a combination of sail RANS computations and analytical models. The boat performance is obtained, in an iterative process, solving the forces and moment equilibrium system of equations. Hull and appendages forces are modelled by analytical formulations. The closure of the equilibrium system is provided by the CFD solution of the sail plan. The procedure permits to find the combination of appendages configuration, rudders setting, sail planform, shape and trim that maximize the VMG (Velocity Made Good). A significant effort was addressed to the selection and evaluation of open-source tools to be adopted in the implementation of the method. The geometric parametric model, which is the core of the procedure, was object of particular attention. The FreeCAD geometric modeller was selected for this task. The sail shapes candidates are automatically generated, within the optimization procedure, by Python scripts that drive FreeCAD to update the geometry according to the variables combination. A very flexible model, able to offer a very wide space of variables, was implemented. This paper describes the implemented geometric model and the environment in which is included.

Keywords

Parametric CAD Open-Source Numerical Optimization Sail design 

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References

  1. 1.
    Claughton, A.R., Shenoi, R.., Wellicome, J.F.: Sailing Yacht Design: Theory. Addison Wesley Longman (1998).Google Scholar
  2. 2.
    Fallow, J.B.: America’s Cup sail design. J. Wind Eng. Ind. Aerodyn. 63, 183–192 (1996).Google Scholar
  3. 3.
    Yoo, J., Kim, H.T.: Computational and experimental study on performance of sails of a yacht. Ocean Eng. 33, 1322–1342 (2006).Google Scholar
  4. 4.
    Viola, I.M.: Downwind sail aerodynamics: A CFD investigation with high grid resolution. Ocean Eng. 36, 974–984 (2009).Google Scholar
  5. 5.
    Ciortan, C., Guedes Soares, C.: Computational study of sail performance in upwind condition. Ocean Eng. 34, 2198–2206 (2007).Google Scholar
  6. 6.
    Cirello, A., Mancuso, A.: A numerical approach to the keel design of a sailing yacht. Ocean Eng. 35, 1439–1447 (2008).Google Scholar
  7. 7.
    Deshpande, A., Riehle, D.: The Total Growth of Open Source. In: Open Source Development, Communities and Quality. pp. 197–209. Springer US, Boston, MA (2008).Google Scholar
  8. 8.
    J.E. Kerwin: A velocity prediction program for ocean racing yachts (revised February 1978). (1983).Google Scholar
  9. 9.
    Philpot, A.B.: Developments in VPP Capabilities. In: Yacht Vision., Auckland, New Zealand (1994).Google Scholar
  10. 10.
    Philpott, A.B., Sullivan, R.M., Jackson, P.S.: Yacht velocity prediction using mathematical programming. Eur. J. Oper. Res. 67, 13–24 (1993).Google Scholar
  11. 11.
    Insel M. and Molland A.: An investigation into resistance components of high speed displacement catamarans. Transaction of the Royal Institute of Naval Architects, (134):1 – 20, (1992).Google Scholar
  12. 12.
    Abbott, H., Von Doenhoff, A.E.: Theory of Wing Sections: Including a Summary of Airfoil Data. Dover Publications, New York (1959).Google Scholar
  13. 13.
    University of Illinois: UIUC wind tunnel data on the web, http://m-selig.ae.illinois.edu/pd.html.
  14. 14.
    Drela, M.: XFOIL: An Analysis and Design System for Low Reynolds Number Airfoils. Presented at the Conference on Low Reynolds Number Airfoil Aerodynamics (1989).Google Scholar
  15. 15.
    Nelder J. A. and Mead R.: Simplex method for function minimization. The Computer Journal, 7:308 – 313 (1965).Google Scholar

Copyright information

© Springer International Publishing AG 2017

Authors and Affiliations

  • Ubaldo Cella
    • 1
  • Filippo Cucinotta
    • 2
  • Felice Sfravara
    • 2
  1. 1.Design Methods aerospace consultingMessinaItaly
  2. 2.Engineering DepartmentUniversity of MessinaMessinaItaly

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