Fluids

Fluids

Can a non streamlined body have lower Cd value?

    • AaronTroll
      Subscriber

      I am trying to calculate the coefficient of drag from a simple geometry that can be seen as an projectile.

      As I understood the more elongated a body is the better (so that there is no wake).

       

      I simulated two different projectiles one as you can see in the mesh and one where the rear pyramidical end is cut off.

       

    • DrAmine
      Ansys Employee
      Parasitic drag contains form and viscous drag components. Just double check convergence of drag forces and run for more iterations before judging the results again. Also please add pictures of the near wall mesh and whether you are resolving boundary layer properly: yplus and number of cells across boundary layer plus the wall grid density.n
    • AaronTroll
      Subscriber
      So i read forum entries on y+ and figured my mesh is not too great as it had no elements close to the wall. Now with the refined mesh the solution is not stable anymore.nThis is the new mesh. element size on the body is 0,01 m if that answeres your question. If not please show me where i can calculate wall grid density and co.nCd is now unstable (0.508677 printed)n
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