# Reply To: SuperLatticePhysWallShearStress3D() returns norm of wall shear stress tensor

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Dear Jonathan,

I have another related problem.

After I have calculated the WSS using SuperLatticePhysWallShearStress3D(). I want to write WSS to disk as a CSV text file for post-processing purposes. I tried two different ways:

1.

a. calculate the WSS using ‘SuperLatticePhysWallShearStress3D<T,DESCRIPTOR> wallShearStressBot(sLattice,superGeometry,4,converter,base)’

b. write data to vtk files, ‘SuperVTMwriter3D<T> vtkWriter(“ellipsoid”);’ then ‘vtkWriter.addFunctor(wallShearStressBotVec);’ and last ‘vtkWriter.write(iT);’

c. extra the WSS using paraview and write WSS as CSV file.

This way is very inconvenient.

2.

a. same as 1.a

b. use the interpolate utility AnalyticalFfromSuperF3D<T> intpolateBotWSS(wallShearStressBot,true); then interpolate the WSS at a given location intpolateBotWSS(WSSBot,loc);

c. write WSSBot and loc to disk.

This way seems better. However, WSS is calculated at a given 2D plane (usually curved) in SuperLatticePhysWallShearStress3D, AnalyticalFfromSuperF3D<T> interpolates the results incorrectly in 3D (the value of WSS outside the plane is 0).

Do you recommend any better ways to write WSS as CSV text to disk?

Regards,

Junwei Guo