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January 19, 2005, 05:25 
Vorticity magnitude

#1 
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Please could someone tell me how to calculate the vorticity magnitude.
Thanks 

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

#2 
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Compute the curl of velocity and take the magnitude of the vector.


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

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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 
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Could this function be defined into any cfd post.


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

#5 
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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  
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Hanxun Yao
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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  
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Filippo Maria Denaro
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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  
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Hanxun Yao
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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  
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Filippo Maria Denaro
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Quote:
Indeed the vorticity vector must be extractet from the antisymmetric matrix.. 

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