Why is the pressure zero at the boundary?

Asalih3d · October 2020

Hello!

I think I have a small misunderstanding, but using the measure tool command like this:

%measuretool% -dirin %%a\data -points wavetankpressvel10pts.txt -onlytype:-all,+fluid -vars:-all,+press,+vel -savecsv

But then looking at the resulting file;

I see that exactly at the boundary the pertubation pressure is exactly 0 at all time steps. How come?

Kind regards

Alex · October 2020

There is a gap between boundary and fluid of the order of "h"

Therefore if you want to compute pressure at a boundary position, please move the point "h" inside the fluid.

This is already explained in some PDF you can find in cases:

examples/main/01_DamBreak

examples/main/05_SloshingTank

Regards

Asalih3d · October 2020

Ah yes I forgot!

I thought that mDBC had completely removed that artifact - seems like it is still there, albeit less, unfortunately. I will keep this in mind for the future.

Kind regards

Alex · October 2020

Wait wait. yes mDBC removes that and there is no need to move the measurement point then!!!!!!!!!!!!!!

Please, just to be sure that water is moving close to the points you have defined in wavetank-pressvel-10pts.txt... add "-savevtk" aswell and plot VTK points in Paraview join with VTK of fluid particles moving so you can see if fluid particles are 2h closer to the pressure gauges.

Regards

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Why is the pressure zero at the boundary?

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