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Techwing: an openFoam case study

Posted by crystal garris on May 2, 2014 at 12:37pm

Hey everyone!

 I am really getting a handle on openFoam. I have figured out the scale and mesh resolution problems I have been having. I can now produce highly detailed data sets of the air flowing over the current techwing design.

tip-vortex.jpg?w=900

this is the airflow over the wing tip. Needs improvement. 

tip-vortex3.jpg?w=900

here is another look from the side the surface is colored with the local pressure numbers. red is highest blue is lowest

negative_p_points.jpg?w=900

This is a view showing the negative pressure contours, represented by colored points.

pillowofair.jpg?w=900This shows the positive pressure contours. 

Now I can make some minor changes to the geometry and see exactly how it will effect performance and flyabilty. Check hobbyuav.com for the latest techwing news.

Tags: cfd, aerodynamics, openfoam, techwing
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Comments

  • Andrew Rabbitt May 12, 2014 at 5:40pm

    Rick, a flying wing offers benefits like reduced wetted area and trim drag and is more structurally efficient, but this aside, it has the same constraints as a conventional layout.  Where it suffers is the size of its lift envelope, which can easily destroy any advantage it begins with.  The CL_max is pretty much done at 0.7-ish, because increased reflex to give you the required pitching moment reduces the CL.  For a conventional layout can see CL_max as high as 1.2 or even beyond.  If landing speed is a key design criteria, then the wing area required for a flying wing is 1.2/0.7-times as great, and since wing area is drag, this has a large impact on cruise and high-speed capability.

  • Rick Williams May 8, 2014 at 3:20am

    the wingtip vortices looks heavy in the first photo.  Will you try to reduces this?  Is your techwing designed to be aerodynamic high performance. I have offen wondered how efficient a wing is compered to something like the techpod witch sets the standard pretty high.

     

  • 100KM
    crystal garris May 6, 2014 at 6:15am
    Thanks andrew. I am 6'7" so should be able to see pretty far. Lol. The motorbike tutorial solves in a few minutes. The techwing case has around 800,000 and solves in about 3 hours running on a single core on a AMD fx-8150 3.6 ghz.
    You can descretize the mesh and run it multi threaded too. It takes a little more set up.
  • Andrew Rabbitt May 6, 2014 at 12:59am

    BTW, how long does a solution take, how many elements and what sort of machinery are you using?

  • Andrew Rabbitt May 6, 2014 at 12:57am

    Nice work Wayne!  I need to stand on your shoulders for a minute and take a look into the future! :)

  • 100KM
    crystal garris May 3, 2014 at 7:26pm
    No, the techwing is an original design. It has a 35 inch wing span.
  • zheng jishi May 3, 2014 at 6:44pm

    Waiting for your instructions eagerly.

    Thanks.

  • zheng jishi May 3, 2014 at 6:23pm

    Hi,wayne,

    great work.Is the "techwing" skywalker X8?

  • 100KM
    crystal garris May 3, 2014 at 6:14pm
    Sure, I can post some step by step instructions.
  • Gary McCray May 3, 2014 at 1:29pm

    Really nice Wayne,

    Maybe you could post some tips on using openFoam or put something on your site.

    Best Regards,

    Gary

This reply was deleted.