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-   -   data extraction of boundary layer thickness over a flat plate (http://www.cfd-online.com/Forums/openfoam-pre-processing/127349-data-extraction-boundary-layer-thickness-over-flat-plate.html)

kick December 9, 2013 11:02

data extraction of boundary layer thickness over a flat plate
 
Hi

I would like to validate my results of flow over a flat plate with blasius solution.
I run the case in simplefoam and i could see my results in parafoam.
However i would like to compare the boundary layer thickness with blasius solution along the flat plate, but unsuccessful in extracting the data from the results i got.

I am trying to extract the data from parafoam is that possible, i also tried using sampledict file but it shows nothing.

How can i extract the data from the results i got.

Please help me with your suggestions.

Thank You
Karthik Goli

schuyler December 9, 2013 15:55

A very simple way (maybe not the most efficient) could be to use the plot on line function in paraview. Plot on a line extending perpendicular from the plate and up into the free stream. Then since the boundary layer thickness is at 99% of the free-stream velocity, you should be able to find this point easily. Then do this at several points depending how much resolution you want along the plate. I think this should work. You'll have to try it yourself.

S.

kick December 9, 2013 22:24

thank you very much for your reply schuyler

Is their any way that i can find the velocity at each and every node above the flat plate, and find out the boundary layer at every point on the flat plate and there by

i want to plot delta vs x1 graph

where delta is the boundary layer thickness and x1 is the length of the plate and compare my solution with blasius solution del=(5*x)/(sqrt(Re))

cheers
kick

schuyler December 12, 2013 16:22

If you want to do it the way I said above with paraview you will probably just have to repeat the process over and over at each point along the plate. You could also export the data to Matlab and try to write a code to do it.

Another idea too (maybe not as helpful), if all you want to do is compare to blasius solution you could also compare the shear stress using the wallshearstress utility and compare it to the blasius solution for shear stress.

Schuyler

kick December 14, 2013 15:45

Hi schuyler

Thank you very much for help you have given me doing this project.

I tried using different functions of paraview but ended up doing it over a line.
I compared the displacement thickness (del) vs length along the flat plate and also coefficient of friction along the flat plate.

kick


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