Flow Past Sphere at High Re - Velocity Behavior

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!
 

boneh3ad

Science Advisor
Insights Author
Gold Member
2,970
637
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.
 

The Physics Forums Way

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top