3 Replies Latest reply on Jul 15, 2008 2:16 PM by Bill McEachern

    Dropping a ball

    1-1NHKU5 Jun 26, 2008 12:44 AM
      A friend asked me if FW can be used to experiment with different shaped objects dropping through the atmosphere. The idea is that air density changes as you come down from very high altitude (25+ miles). Drag, terminal velocity, surface heating, etc. change as the object drops closer to the surface.

      If possible, how would one setup such a simulation?

      -Martin
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        • Dropping a ball
          Basil Gello
          Basil Gello Jun 27, 2008 8:58 AM (in response to 1-1NHKU5)
          Martin,

          that can be done using the external analysis with variable density dependent on time / altitude... but with the thermal effects that is pure bit complicated Cause the primary source of heat here is sticky friction caused by very large object velocity, you will have to specify the dependency and then, probably, apply it to the outer surfaces of your object. Apparently, to simulate speed downgrade you should use Motion too...

          Or, there were some articles about object - through - viscous environment passing (probably in ANSYS, I can't remember). Look for them and find what you need.

          Regards, Basil.
            • Dropping a ball
              1-1NHKU5 Jul 8, 2008 2:30 PM (in response to Basil Gello)
              I might play with the idea just for fun. Thanks.

              This came out of a conversation where the question of whether or not a 10lbs steel ball dropped from 45,000 feet could break the sound barrier. I said "I don't know, but we just got FloWorks, it might be able to tell us"

              You work engineers for 12 hours a day enough days in a row and stuff like this is what comes out!

              -Martin