Flow Past Sphere at High Re - Velocity Behavior

AI Thread Summary
The simulation of airflow around a sphere at 450 m/s reveals a significant decrease in velocity ahead of the sphere, likely due to shock wave formation. This phenomenon occurs because the flow speed exceeds the speed of sound, resulting in a bow shock rather than an attached oblique shock. The observed cut plot indicates a pressure increase in the green zone, correlating with the velocity drop. The blunt shape of the sphere contributes to this flow behavior. Understanding these dynamics is crucial for accurate simulations in high-speed aerodynamics.
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.
 

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