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-   -   Shock wave - how? (https://www.cfd-online.com/Forums/cfx/25685-shock-wave-how.html)

Mareike April 19, 2008 08:47

Shock wave - how?
 
Hi there,

I want to plot the shock waves and the expansion waves of a flow around a flat plate. The simulation is done... How can I plot that inside CFX Post? I want to see the different angles.

Thanks a lot! Mareike

Glenn Horrocks April 20, 2008 18:24

Re: Shock wave - how?
 
Hi,

Have a look at tutorial 8, Supersonic flow over a wing.

Glenn Horrocks

Mareike April 20, 2008 19:54

Re: Shock wave - how?
 
hi glenn,

thanks a lot!

ehm... what must i do to see the skin friction?

Glenn Horrocks April 21, 2008 18:46

Re: Shock wave - how?
 
Hi,

This tutorial has a free slip boundary on the wing so you won't get any skin friction. You will have to rerun it with a no-slip wing to get skin friction. Also note to get accurate skin friction you will need a much finer mesh than the tutorials use.

Glenn Horrocks

ayush1511 October 27, 2023 04:32

shock wave position Vs time plot for any parameter like pressure or density or mach
 
I have a query... How to plot shock wave position Vs time plot in ANSYS Fluent or CFD post-processor for any particular parameter like pressure or mach no. or density?

ghorrocks October 27, 2023 23:36

This is the CFX forum. For fluent try the fluent forum.

But to visualise the shock waves, don't you just draw a cross section of pressure, density or velocity or something like that? Isn't that obvious? Or are you asking something else? (if so please explain what you are trying to do more thoroughly)

ayush1511 October 29, 2023 10:06

I performed a 2D simulation of the shock wave in shock tube using shock capturing method. Now I want to plot a graph of x-t (x co ordinate vs. time) for the shock wave in the shock tube. It was a unsteady with turbulent model, simulation using the Ansys Fluent. So, is there any way that I can plot x-t graph for the shock wave using the Ansys Post-Processing??

Thank You.

Gert-Jan October 29, 2023 11:24

If you have Fluent .dat-files at intermediate time timesteps, then you can read these into CFD-Post using the Timestep-Selector-Icon. In this way you can plot the variables as a function of time and export graphs.
If you dont have intermediate files, then you have to rerun the case and make sure you save these.

ayush1511 October 29, 2023 12:07

In "x Vs t" plot, x is the length of the shock tube along which shock wave is moving.

Gert-Jan October 29, 2023 12:28

You can draw a line through your tube and plot the variable x as a function of length. This you can export to a .csv-file, Do this for every time step (using you timestep selector icon) and you will have multiple .csv-files. Plot them in a spreadsheet, ét voila.
You can also write a script to let Post read the .dat-files and write the .csv-files. Then it goes automatically.

Possibly you can open multiple .dat-files into one Post session. Then you might get multiple lines in one plot in CFD-Post. I never tried. Please try.

ghorrocks October 29, 2023 16:48

I would export the pressure data (or density, velocity or whatever shows the shock clearest) as a CSV file and write a thing in python or matlab to find the shock and determine the x position. Then script it over all the time points and you have a shock position versus time curve.

Gert-Jan October 29, 2023 19:49

Quote:

Originally Posted by ayush1511 (Post 859080)
In "x Vs t" plot, x is the length of the shock tube along which shock wave is moving.

This will be a boring curve, not?
With 'x' the length of the tube as a function of time..........??


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