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-   -   graph of velocity against distance (http://www.cfd-online.com/Forums/fluent/105849-graph-velocity-against-distance.html)

 zaynah04 August 10, 2012 13:02

graph of velocity against distance

Dear everyone..

I am relatively new to fluent, I had done a 2D simulations of some buildings and i want to plot a graph of velocity against distance..

the problem is that in the drop down menu for surfaces i see a lot of options, hence i am confused...i also see a lot of zones in the drop down menu..

please i really need someone to guide me in that..

zay

 Touré August 10, 2012 17:31

Go to Mesh -> Display
Then you can select on surface and click on Display to know which surface it.
Do it for all surfaces. to understand the relation between the names and the geometry.

 zaynah04 August 11, 2012 03:32

Thanks You a lot Toure..

it helped....

In my plot now, when i am plotting velocity against distance, what parameter should i normally use for the surface?
I mean i want to compare two graphs in my project, hence i am confused on the parameters displayed...

 Touré August 11, 2012 11:08

If you want to have a map color of any variable on a surface such as the pressure :
Graphics and animation -> Contours
Then select filled in "Options", the variable in "Conours of" and the surfaces in "Surfaces"

If you want to plot any variable versus of any other variable on a line (velocity vesus distance) :
Plots -> XY Plot
Be sure that Position on X Axis and Position On Y Axis are not selected in the "Solution XY Plot" window
Click on New surface and select Line/Rake in the "Solution XY Plot" window
Draw the line you want to plot in the "Line/Rake Surface" window
Draw a line that represent distance for you
Close the "Line/Rake Surface" window
Then select the variable for X axis and the variable for Y axis in the "Solution XY Plot" window
Click on Plot.
If you want to export the data of the graph to a file , select "Write to File".
Then your "Plot" button become a "Write" button. Click on it and save the plot data to a file. You can reload many files with the "Load" button on the same graph.

 zaynah04 August 11, 2012 16:01

Thank you a lot Toure..

You told me what i could not find in books..

I am grateful..

zay

 Touré August 11, 2012 23:20

Keep going

 zaynah04 August 12, 2012 14:42

dear toure..
Fluent solve a lot of equations. including the Navier-Stokes one.

how do i know which equation solve for example in a laminar flow around a cube or circle?

 Touré August 12, 2012 15:21

I don't understand the question. You chose the equations by selecting a model in Models
1. Models -> Viscous (Inviscid, Laminar or Turbulent models such as k-epsilon and others)
2. You can add heat transfer Models-> Energy (On)
3. .....

 zaynah04 August 12, 2012 15:24

i want to knnow all the equations which fluent solve to get the result.
example, when i model a cube in laminar flow or turbulent, i iterate and get the result. i want to know which equations did fluent use for that?

thanks

 Touré August 12, 2012 20:22

It's ANSYS FLUENT Theory Guide that you need
A not too new version but it does change a lot between version 12, 13 and 14
https://www.sharcnet.ca/Software/Flu...df/th/flth.pdf

 zaynah04 August 14, 2012 01:16

i am using fluent 6.3... but am studying the book..

thanks toure...

 zaynah04 August 14, 2012 01:36

hi,

After i itererate my program ( turbulent) and after convergence is reached , when i display velocity contour i got error messages.

"Error message from graphics function Compute_Text_Extent:
The device for '/driver/msw/win+w0/inner/scale' doesn't seem to be alive

Error: Floating point error: invalid number

Error Object: ()"