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Flow Past Sphere at High Re - Velocity Behavior

  1. Mar 29, 2014 #1
    I'm currently working on simulations in Solidworks of the flow of air (v = 450 m/s)
    around a sphere (radius = 1.5 cm). The results have been used in a cut plot
    representing the velocity in the x direction. The image is similar to this one:
    (Purple is high velocity and red is low velocity)
    I was wondering why the velocity suddenly decreased so far in front of the
    sphere and so spaced out (green zone), and then increases again.
    Thank you for any answer!
  2. jcsd
  3. Mar 29, 2014 #2


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    Science Advisor
    Gold Member

    That looks a lot more like a plot of pressure than a plot of velocity to me. At any rate, I don't know what conditions these simulations were run at, but 450 m/s is likely above the speed of sound, so the reason you see a sudden increase in pressure (and decrease in velocity) is because a shock wave is going to form. It happens out in front of the sphere because the sphere is rather blunt, and so you get a bow shock instead of an attached oblique shock.
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