CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Main CFD Forum

Velocity Fields/Stream Equations

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   February 16, 2003, 23:29
Default Velocity Fields/Stream Equations
  #1
beginner
Guest
 
Posts: n/a
hi

I am making a small cfd code and want to test my output in different flow fields

i want to test my output in a rotational / translation/ revolving flow field and any combination of these . could anyone tell me how to get the stream function corresponding to these

thanks a newbie
  Reply With Quote

Old   February 17, 2003, 03:37
Default Re: Velocity Fields/Stream Equations
  #2
Praveen
Guest
 
Posts: n/a
If you have the velocity field tecplot can plot the streamlines. You can even use matlab (stream2, stream3, streamline).
  Reply With Quote

Old   February 17, 2003, 13:34
Default Re: Velocity Fields/Stream Equations
  #3
Jim Park
Guest
 
Posts: n/a
"rotational / translation/ revolving flow field"?

Does this mean it's a three dimensional (x - y - z) flow? If so, the stream function will be a vector function and so not too useful for visualization of the flow.

To get a stream function that's scalar, your flow must be 2-d, either Cartesian (x - y) or cylindrical (r - z although a rotational component can be included if it's axisymmetric).

You can visualize the flow using virtual particle traces or streaklines. Generate the tracks for those by for a series of points (x, y, z)_i by

x_i+1 = x_i + u(x_i, y_j, z_k)*dx

with similar for y_j+1 and z_(k+1).

Hope this helps.
  Reply With Quote

Old   February 17, 2003, 14:53
Default Re: Velocity ... corrected post!
  #4
Jim Park
Guest
 
Posts: n/a
My previous reply to this was a bit hasty. See correction in the partical trace discussion below:

"rotational / translation/ revolving flow field"?

Does this mean it's a three dimensional (x - y - z) flow? If so, the stream function will be a vector function and so not too useful for visualization of the flow.

To get a stream function that's scalar, your flow must be 2-d, either Cartesian (x - y) or cylindrical (r - z although a rotational component can be included if it's axisymmetric).

You can visualize the flow using virtual particle traces or streaklines. Generate the tracks for those by for a series of points (x, y, z)_i by

*** Corrected text below ***

x_i+1 = x_i + u(x_i, y_i, z_i)*dx

with similar for y_i+1 and z_(i+1).

For the particle coordinates (x, y, z), the index "i" counts the locations generated for the virtual particle through the flow field. It is NOT an index for a grid line or node.

Hope this helps.

  Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
UDF error - parabolic velocity profile - 3D turbine Zaqie Fluent UDF and Scheme Programming 8 May 11, 2014 08:34
Problem with assigned inlet velocity profile as a boundary condition Ozgur_ FLUENT 2 August 3, 2012 05:54
Emergency:UDF for a time dependent parabolic velocity zumaqiong Fluent UDF and Scheme Programming 12 March 25, 2010 13:00
Influece of wall velocity in the main flow marvin CFX 0 March 22, 2008 03:05
what the result is negatif pressure at inlet chong chee nan FLUENT 0 December 29, 2001 06:13


All times are GMT -4. The time now is 23:51.