
[Sponsors] 
January 19, 2005, 05:25 
Vorticity magnitude

#1 
Guest
Posts: n/a

Please could someone tell me how to calculate the vorticity magnitude.
Thanks 

January 19, 2005, 10:04 
Re: Vorticity magnitude

#2 
Guest
Posts: n/a

Compute the curl of velocity and take the magnitude of the vector.


January 20, 2005, 14:21 
Re: Vorticity magnitude

#3 
Guest
Posts: n/a

wx = dw/dy  dv/dz wy = du/dz  dw/dx wz = dv/dx  du/dy
w = wx(i) + wy(j) + wz(k) vorticity magnitude = sqrt(w.w) = sqrt( wx*wx +wy*wy +wz*wz) 

January 21, 2005, 22:59 
Re: Vorticity magnitude

#4 
Guest
Posts: n/a

Could this function be defined into any cfd post.


August 17, 2011, 10:07 
or with vorticity tensor

#5 
Member
Join Date: May 2010
Posts: 44
Rep Power: 9 
w=wij
where wij is the vorticity tensor defined as the antysymmetric part of the velocity gradient tensor. Its magnitude defined by: wij=sqrt(2wij*wij) and its the same as the magnitude of the vorticity vector as defined earlier. 

March 2, 2016, 01:01 

#6  
New Member
Hanxun Yao
Join Date: Feb 2016
Posts: 5
Rep Power: 3 
Quote:
Hi, If I define a antisymmetric matrix as: 0 x y x 0 z = A y z 0 which is similar to Vorticity tensor, but when I calculate A*A, I got 2*x^22*y^22*z^2 which is negative and has problem under square root. Could you please tell what causes this problem. Thank you very much. 

March 2, 2016, 04:33 

#7  
Senior Member
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 3,565
Rep Power: 40 
Quote:
I do not understand what you did ... if you want to define a measure for a matrix, you should define some norm on that A, this is not so simple. You can define an induced norm by using a (non vanishing) vector x such that A.x/x 

March 2, 2016, 07:04 

#8  
New Member
Hanxun Yao
Join Date: Feb 2016
Posts: 5
Rep Power: 3 
Quote:
Thank you for your reply, Now I know what is the norm of a matrix, then I still have a question: What is the magnitude of vorticity, seems like it is not equal to the norm of vorticity tensor. thanks again. 

March 2, 2016, 07:11 

#9  
Senior Member
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 3,565
Rep Power: 40 
Quote:
Indeed the vorticity vector must be extractet from the antisymmetric matrix.. 

Thread Tools  
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Vorticity magnitude  makaero  FLUENT  0  May 25, 2011 20:30 
vorticity boundary condition  bearcharge  Main CFD Forum  0  May 14, 2010 11:32 
magnitude of vorticity using fluent  ryan  Main CFD Forum  1  November 30, 2009 17:29 
Could vorticity magnitude be ploted ?  w0er  Main CFD Forum  4  February 8, 2005 08:49 
Vorticity magnitude  Hernani  Siemens  2  August 20, 2001 09:48 