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-   -   vorticity from tecplot (http://www.cfd-online.com/Forums/tecplot/70723-vorticity-tecplot.html)

HaKu December 3, 2009 13:15

vorticity from tecplot
 
hey

i have the data for velocities ..

i want to know tht whether tecplot can give me the vorticity contours as well or do i need to calculate it first from my code and thn i cn see it in tecplot??

if its the second case wht is formula to calculate vorticity so i cn use it in my finite diffeerence code..

regards

CFDtoy December 3, 2009 14:25

vorticity plt
 
use the calculator available in tecplot - compute the cross product of gradient and velocity vector and get a vector. Remember - vorticity is a vector..not a scalar...

Quote:

Originally Posted by HaKu (Post 238627)
hey

i have the data for velocities ..

i want to know tht whether tecplot can give me the vorticity contours as well or do i need to calculate it first from my code and thn i cn see it in tecplot??

if its the second case wht is formula to calculate vorticity so i cn use it in my finite diffeerence code..

regards


HaKu December 3, 2009 16:01

any idea to get it directly from the code???

ski December 3, 2009 16:05

In the version of tecplot I'm using (tecplot 360 2008, linux) I click on the `analyze' menu and select `calculate variables'. I can then select vorticity and can then plot contours of the x-vorticity, y-vorticity etc. I'm sure other versions of Tecplot will have similar options.

HaKu December 3, 2009 16:34

hey ski

does it work even if u r not calucating vorticity seperatly in the code??

ski December 3, 2009 16:45

I believe Tecplot calculates the vorticity from your velocity field so there is no need for you to calculate vorticity in your code.

HaKu December 3, 2009 23:45

thanks .. i will try and see how it goes..

CFDtoy December 4, 2009 10:27

in code
 
Just use the vector cross product of grad and u. You have u - u1, u2, u3, grad operator along gradx,grady,gradz (d/dx,d/dy,d/dz) - just take any test book and you will have grad X v = vorticity vector array. Read them and plot in tec or fieldview or any other.


Quote:

Originally Posted by HaKu (Post 238683)
thanks .. i will try and see how it goes..


HaKu December 4, 2009 12:13

yes sir i got it now

niravtm007 September 4, 2011 01:06

time vs velocity grpah
 
i have used a udf to get a sinusoidal velocity input. can any one please show how can i use this data files from fluent to tec plot to get a time vs velocity graph so i can see if its varying sinusoidally or not.

cfdnewbie September 4, 2011 06:33

I would advise you against using the tecplot build in function. We have found that its vorticity calculation is far inferior to the one done within the code! Your best approach is to compute it from the velocity field yourself, and have tecplot just display it!

scott_rumage May 25, 2012 12:18

Cfdnewbies comment above is correct -- older versions of Tecplot 360 were not as accurate as they should have been in the calculation of vorticity.

However, the release of Tecplot 360 2012 reworked the calculations at the boundary nodes resulting in an improvement in the accuracy of the vorticity result.

Scott

http://www.tecplot.com/Solutions/Pro...ecplot360.aspx

mohammad September 3, 2012 11:34

A real problem in techpolt
 
Hey everybody....
I have got a big problem with Techplot.
I have the results of vorticity in in my domain in CFX. However, when i export to it to *.CSV and then convert it to *.DAT the Techplot gives me connectivity error.
Amazingly, the velocity of the same domain (or plane) can be shown in techplot without any problem...

can anyone tell me why?
Does the Techplot have some problem with vorticity data....PLZ note that every bit of the files of the vorticity and velocity are the same, except the velocity is replaced vorticity.

thanks in advance

W.T.S May 18, 2013 05:51

vorticity in a cylindrical coordinate
 
Quote:

Originally Posted by cfdnewbie (Post 322816)
I would advise you against using the tecplot build in function. We have found that its vorticity calculation is far inferior to the one done within the code! Your best approach is to compute it from the velocity field yourself, and have tecplot just display it!

Do you know how to calculate tangential vorticity, maybe it's not called tangential vorticity, i mean the vorticity in a cylindrical coordinate.Thank you!!!

taxalian May 18, 2013 16:38

Hi Wang,

I would try the coordinate transformation from cylindrical to rectangular and then calculate the vorticity. Alternate way is to calculate the vorticity directly in the cylindrical coordinates.

W.T.S May 18, 2013 23:58

Thankyou very much!
 
Quote:

Originally Posted by taxalian (Post 428476)
Hi Wang,

I would try the coordinate transformation from cylindrical to rectangular and then calculate the vorticity. Alternate way is to calculate the vorticity directly in the cylindrical coordinates.

Thank you for your help! If calculate the vorticity in the cylindrical coordinate, we can only get the x,y,z vorticity. But since I need the Vtheta,Vr,Vz, to display my data in a cylindrical coordinate, I think the cyclindrical coordinate is better. Infact, the only problem for me now is how to calculate the first order derivative ddr, but the calculation of ddr is only works in polar line 2D, while need a 3d solution.Could you help me with this? Thank you very much! By the way, how can I define a "if" statement in tecplot?

JAY ADHVARYU October 1, 2013 10:45

How i get the streamline plot and total pressure plot in techplot? pls help me i am beginer, i have portable techplot 360 2009 R1 12.0.0.4231.

I also go to anlyze then calculate variable but there is no option for total pressure and stream line plot.


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