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Dimensionless Velocity above 1

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Old   August 28, 2024, 09:05
Unhappy Dimensionless Velocity above 1
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Joe
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I am new to SU2 and I'm plotting an incompressible laminar flat plate against the blasius equation on paraview. In paraview, my dimensionless velocity X components rise from 0 to 1.05 instead of just 1.

First I thought it was for the negative symmetry x values but even on the positive side there are Vs above 1.
I thought perhaps its my dimensionless viscosity as I have no idea how the reference viscosity of 7.5 is determined, but I haven't found a way to change it.
I have tried recomputing my mesh after chatGPT told me I could have too fine a mesh causing instability but the outcome was the same.
I have fiddled with my cfg removing and adding reference values among other things but nothing seems to work.
Perhaps it is my misunderstanding of the dimensionless values. I am trying to plot eta = y*SQRT(freestream V/vx) against f'(eta) = u/freestream V, an i have assumed velocity_X is f'(eta), though I have also tried different combinations of working to it. I have also assumed vx is laminar viscosity, for which i have used the dimensionless value in the eta calculation. To do this i used the paraview calculator function.

I created my mesh in ICEM CFD, converted from CGNS to su2.

density = 1.225, kinematic viscosity = 0.0000148m^2/s, plate length = 0.6m & Reynolds number = 248529.
Attached Images
File Type: jpg Paraview Spreadsheet.jpg (159.4 KB, 3 views)
File Type: jpg My velocity X vs Blasius.jpg (71.5 KB, 3 views)
Attached Files
File Type: txt FLAT_PLATE3.su2.txt (140.2 KB, 1 views)
File Type: txt log_FLAT_PLATE.txt (42.1 KB, 0 views)
File Type: txt FLAT_PLATE.cfg.txt (10.7 KB, 2 views)
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Old   August 28, 2024, 16:23
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bigfoot
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If you look at the tutorial for the flat plate, you see that the plate does not start at the inlet but downstream. This is to prevent interaction between the inlet and the flat plate. There is now an increase of the freestream velocity due to this interaction.

You can maybe start by using the flat plate mesh for your case and see if that already solves the issue.



https://su2code.github.io/tutorials/Laminar_Flat_Plate/
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