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

Non Dimensional Parameters

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

LinkBack Thread Tools Search this Thread Display Modes
Old   June 28, 2000, 16:36
Default Non Dimensional Parameters
Posts: n/a
Does anyone know the non dimensional group assocaited with vorticity.

I derived the following, via Non Dimensional Analysis, but @ present I am not to sure if its correct. (Is Rads already Non Dimensional????)

Vorticity*=Vorticity*Char_lenght^2*kinematic viscoity/free stream circulation^2.

Also can anyone give me a decent definition of Rossby number.

Again thanks for the advice.
  Reply With Quote

Old   June 28, 2000, 20:12
Default Re: Non Dimensional Parameters
John C. Chien
Posts: n/a
(1). In fluid dynamics, the free stream condition is normally taken as a reference state. (there are other parameters one can use, such as the wall states)(2). It is convenient, because one can get a feeling about the change of the fluid states downstream of the inlet state. (3). The free stream reference state can be taken as U_free, P_free, T_free, Vorticity_free, etc... (4). In this case, the flow variable become, u/U_free, p/P_free, t/T_free, vorticity/Vorticity_free, etc... (5). One can also express Vorticity_free in terms of other free stream variables through its definition. (6). When the length is involved, the characteristic length, such as the inlet diameter, of the length of the body can be used. (7). I think, it is important to recognize that, the purpose of doing this is to make the variation of the flow field variable easier to understand. I mean the distance between the reference state and the local state. Otherwise, even if the final variable is dimensionless, it is hard to understand the behavior. Thus, it becomes useless.
  Reply With Quote


Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Reverse rate parameters with CHEMKIN imports Kevin L FLUENT 1 June 27, 2013 04:22
twoPhaseEulerFoam - parameters grjmell OpenFOAM 1 June 16, 2011 08:13
units of geometrical parameters lost SoobY ANSYS Meshing & Geometry 2 January 10, 2011 03:58
non dimensional analysis rosol FLUENT 1 June 1, 2007 10:51
New to CFX-need explanations about mesh parameters Cyril CFX 3 November 24, 2006 06:33

All times are GMT -4. The time now is 08:08.