Recent Content by jlconger

  1. jlconger
    Post

    CFD sail trim optimization

    Joakim, I'm sure you are right, but since I'm doing all of this just for my own enjoyment, I think I will pursue option 2 a bit further just to...
    Post by: jlconger, Oct 29, 2014 in forum: Hydrodynamics and Aerodynamics
  2. jlconger
    Post

    CFD sail trim optimization

    What I've learned I'll put my head back on the block and attempt to summarize what I've learned from all of this excellent discussion. In...
    Post by: jlconger, Oct 29, 2014 in forum: Hydrodynamics and Aerodynamics
  3. jlconger
    Post

    CFD sail trim optimization

    My 'optimization' is only partially automated. The input defines a series of sail shapes to run at one apparent wind speed and direction. I've...
    Post by: jlconger, Oct 27, 2014 in forum: Hydrodynamics and Aerodynamics
  4. jlconger
    Post

    CFD sail trim optimization

    Let me propose this thought experiment, and see if it can help resolve my conceptual problem. 1) I want to estimate the force created by a sail...
    Post by: jlconger, Oct 27, 2014 in forum: Hydrodynamics and Aerodynamics
  5. jlconger
    Post

    CFD sail trim optimization

    Thanks - Setting an a boundary condition with more wind sheer makes sense and is easy to do. I'm afraid I still do not follow your second point...
    Post by: jlconger, Oct 27, 2014 in forum: Hydrodynamics and Aerodynamics
  6. jlconger
    Post

    CFD sail trim optimization

    Clearly hit a nerve here... Always interesting when new approaches receive such loud criticisms. Rather than defend the Navier-Stokes equations,...
    Post by: jlconger, Oct 27, 2014 in forum: Hydrodynamics and Aerodynamics
  7. jlconger
    Post

    CFD sail trim optimization

    I believe the papers on the subject you are referring to are in the case where you are simulating 2D cross sections of sails at different...
    Post by: jlconger, Oct 26, 2014 in forum: Hydrodynamics and Aerodynamics
  8. jlconger
    Post

    CFD sail trim optimization

    OK - got it. This is the effect of the vertical wind speed gradient on the the apparent wind vs elevation. And yes, that is included in the model....
    Post by: jlconger, Oct 26, 2014 in forum: Hydrodynamics and Aerodynamics
  9. jlconger
    Post

    CFD sail trim optimization

    Perhaps you are thinking of a different frame of reference? In this model the boat is fixed in the center of the grid and the airflow moves by it....
    Post by: jlconger, Oct 26, 2014 in forum: Hydrodynamics and Aerodynamics
  10. jlconger
    Post

    CFD sail trim optimization

    This model simulates a 100m x 100m x 50m high box of air with the 10m boat in the center. Drag from the water surface results in a wind speed...
    Post by: jlconger, Oct 26, 2014 in forum: Hydrodynamics and Aerodynamics
  11. jlconger
    Post

    CFD sail trim optimization

    Thanks for your thoughtful reply. As you say, this 'optimization' takes the sails to places that I can't really go with my own boat with real...
    Post by: jlconger, Oct 26, 2014 in forum: Hydrodynamics and Aerodynamics
  12. jlconger
    Thread

    CFD sail trim optimization

    I have been experimenting with using a 3D OpenFOAM CFD model to 'optimize' sail trim. The test case is a J/32 fractional sloop. The CFD model has...
    Thread by: jlconger, Oct 23, 2014, 62 replies, in forum: Hydrodynamics and Aerodynamics
  13. jlconger
    Post

    sail equivalent to winglets?

    pictures of top and bottom vortexes Here are a couple of views of both vortexes from a CFD simulation. It is clearly going to depend on the boat...
    Post by: jlconger, Sep 22, 2014 in forum: Hydrodynamics and Aerodynamics
  14. jlconger
    Post

    sail equivalent to winglets?

    It still looks to me that the winglets are on the wrong end of the sail. The big vortex is at the foot, not the head of the sail. When I get time...
    Post by: jlconger, Sep 21, 2014 in forum: Hydrodynamics and Aerodynamics