CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > CFX

viscous force: Cfx : wrong formulation ????

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

LinkBack Thread Tools Display Modes
Old   May 11, 2006, 09:17
Default viscous force: Cfx : wrong formulation ????
Posts: n/a
I read from CFX 10.0 Theory Book, that Cfx uses this formulation for the viscous forces:

--------------------------------------------------------- Viscous Forces = coeff_viscous * (u_i,j+u_j,i),j --------------------------------------------------------- where: u_i := is the i-th component of the velocity u= (u,v,w)

and u_i,j = is the j-spatio-derivative by the j-th space direction.

from the Text book, the correct formulation, valid for all fluid (incompressible and compressible both) is:

--------------------------------------------------------- Viscous Forces = coeff_viscous * (u_i,j+u_j,i),j-2/3*(u_k,k)*delta_Kronecker(i,j) ---------------------------------------------------------

Why ???????????????
  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
Pros and Cons for CFX, CFdesign, COMSOL Val Main CFD Forum 3 June 10, 2011 02:20
CFX pressure in Simulations problem nasdak CFX 1 April 14, 2010 13:22
User-defined force transfer across FSI interface vivekcfd CFX 7 March 10, 2010 21:43
CFX 4.4 installation problem Pandu Sattvika CFX 1 December 1, 2001 05:07
How to obtain correct viscous pressure drag using CFX? Ketut Utama Main CFD Forum 1 January 25, 1999 06:05

All times are GMT -4. The time now is 18:18.