CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Post-Processing

Obtaining wallShearStress as lineplot with OpenFoam

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   August 8, 2022, 11:26
Default Obtaining wallShearStress as lineplot with OpenFoam
  #1
New Member
 
Tim
Join Date: Jun 2022
Posts: 2
Rep Power: 0
Tim_solver is on a distinguished road
Hi all,

I am performing a series of simulations in CFD and in order to pinpoint the location of separation on my body I would like to plot the skin friction coefficient (and thus the wall shear stress) as a lineplot (x-axis: x/c location, y-axis: Cf) such that it is clear where the crossover point is (i.e. the wall shear stress changes sign).

I want to circumvent Paraview entirely since quite some configurations have to be run which means that manual post-processing is time intensive. Essentially, I would like to generate a file (preferably .txt or .raw or similar format) with the x,y,z coordinates and the wall shear stress (preferably as a vector) such that it can be post-processed in python.

I've already tried to sample the wallShearStress on the surface after using postProcess -func wallShearStress -latestTime. This does return a file in the format I want, however, since it samples the volume values (which are zero for the wallshearstress) it returns a vector which is zero in all directions.



Does anybody know a way to obtain the desired result? Scouring the internet turned out to be fruitless unfortunately.


Many thanks in advance!

Last edited by Tim_solver; August 9, 2022 at 03:28. Reason: Incorrect statement
Tim_solver is offline   Reply With Quote

Old   August 15, 2022, 04:00
Default Solution
  #2
New Member
 
Tim
Join Date: Jun 2022
Posts: 2
Rep Power: 0
Tim_solver is on a distinguished road
Hi all,

For whoever might be interested later on, I've found a solution.

First one need to calculate wallShearStress with the appropriate post process function.

Then after reconstructing (if multiple cores are used) one can use the foamToVTK function to write the coordinates and the wallshearstress vector at each coordinate. Depending on the imported geometry one might need to order the data such that a lineplot can be made (suggestion: just find the nearest point). If you don't like to bother ordering the data, you can also make a scatter plot as a quick and dirty fix.
Tim_solver is offline   Reply With Quote

Reply

Tags
lineplot, openfoam, post-processing, python, wallshearstress


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Map of the OpenFOAM Forum - Understanding where to post your questions! wyldckat OpenFOAM 10 September 2, 2021 05:29
OpenFOAM Training Jan-Apr 2017, Virtual, London, Houston, Berlin cfd.direct OpenFOAM Announcements from Other Sources 0 September 21, 2016 11:50
why does 'sample' do this? wallShearStress question CHARLES OpenFOAM Post-Processing 0 August 7, 2013 19:30
Cross-compiling OpenFOAM 1.7.0 on Linux for Windows 32 and 64bits with Mingw-w64 wyldckat OpenFOAM Announcements from Other Sources 3 September 8, 2010 06:25
Adventure of fisrst openfoam installation on Ubuntu 710 jussi OpenFOAM Installation 0 April 24, 2008 14:25


All times are GMT -4. The time now is 22:09.