CFD Online Logo CFD Online URL
Home > Forums > Main CFD Forum

Purpose of streamlines in unsteady flow

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

LinkBack Thread Tools Display Modes
Old   January 31, 2011, 18:29
Default Purpose of streamlines in unsteady flow
Senior Member
Join Date: Mar 2009
Posts: 148
Rep Power: 10
quarkz is on a distinguished road

I have seen diagrams of airfoil with streamlines drawn. It helps to show the velocity vectors of the flow around the airfoil.

However, does streamlines help in the analysis of unsteady flows, such as an airfoil moving up and down? Is there any useful information which can be extracted?

quarkz is offline   Reply With Quote

Old   February 1, 2011, 11:30
Join Date: Mar 2009
Posts: 74
Rep Power: 10
otd is on a distinguished road
Streak lines can be useful for visualization.

One way:
Create an imaginary particle at points of interest (x, y).
Follow the particle in a Lagrangian frame.

Example: Dx/Dt = u, Dy/Dt = v, Dz/Dt = w so

x(t+dt) = x(t) + u*Dt, etc. following the particle through the flow.
The three equations can be integrated explicitly [use u(x, t)], implicitly [use some combination of u(x,t) and u(x+dx, t+dt) estimates]. The u's, v's and w's are interpolated from your CFD solutions at the various (x,y,z,t). Implicit schemes and various Runge-Kutta schemes are available.

I'm sure other folks will correct, extend, and clarify this outline!

otd is offline   Reply With Quote


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
Question on Unsteady Flow Ben CFX 5 January 17, 2008 18:04
Oscillation (losing stability) ---> unsteady flow? HT Main CFD Forum 1 February 25, 2004 13:29
output data for unsteady flow case wieke Main CFD Forum 0 September 30, 2003 04:40
CFX- Particle tracking in Unsteady flow faithkim Main CFD Forum 3 September 14, 1999 20:57
computation about flow around a yawed cone Tylor Xie Main CFD Forum 0 June 9, 1999 07:33

All times are GMT -4. The time now is 17:35.