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Discuss installation & licensing of our Ansys Teaching and Research products

AQWA Vortex Shedding Effect On Bilge Keels

    • Erhan Sokmn


      Im currently working on my MSc and i want to make a roll damping analysis. I convinced my lecturer that it is possible to make this study in AQWA but he finally asked me to consider that AQWA use potential theory, thus it is not possible to consider friction between water and bilge keels. When i check the theory guide and user guide i couldn't find anything about if AQWA consider the friction or not.

      In this case, is the friction calculated by AQWA?

      Best Regards,


    • Ingrid Machecler
      Ansys Employee


      it is correct that the fluid viscosity is not explicitly taken into account in Aqwa.

      However, the vortex shedding effect is accounted for by the program based on the roll motion, the Keulegan-Carpenter number and the roll natural frequency of the vessel. The bilge keel non-linear roll damping is based on the 2011 ITTC's recommended procedure and includes the K-C number in its calculation.

      I hope this helps.

      Kind regards,


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