Flow Past Sphere at High Re - Velocity Behavior

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SUMMARY

The discussion focuses on the simulation of airflow around a sphere at a velocity of 450 m/s using Solidworks. The results indicate a significant decrease in velocity ahead of the sphere, attributed to the formation of a bow shock due to the blunt shape of the sphere. This phenomenon occurs when the flow speed exceeds the speed of sound, leading to a sudden increase in pressure and a corresponding decrease in velocity in the region ahead of the sphere.

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  • Understanding of fluid dynamics principles, particularly shock wave formation.
  • Familiarity with Solidworks simulation tools and settings.
  • Knowledge of airflow characteristics around objects, specifically spheres.
  • Basic concepts of pressure and velocity relationships in compressible flow.
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redpepper303
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Hello,
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:
https://www.llnl.gov/str/December01/gifs/Naka3.jpg
(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!
 
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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.