Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Flow Past Sphere at High Re - Velocity Behavior

Flow Past Sphere at High Re - Velocity Behavior

Flow Past Sphere at High Re - Velocity Behavior

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!

RE: Flow Past Sphere at High Re - Velocity Behavior

Under standard conditions your flow is supersonic. What you are seeing is a shock wave. This is where the velocity changes suddenly (slows) with an attendant increase in pressure and temperature. After a short time/distance the pressure re-accelerates the air, but to lower than stream velocity.

Since it is a blunt object, the shock wave is detached. If you substitute a sharp edged item, the shock wave will be an attached shock wave on the edge of the item. The shock wave can't attach to the sphere because the air at the sphere has already come to a stop and has stopped the air in front of it, up to the place that is in equilibrium with the shock wave.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close