Dear Emilie, Evan and Simone,
as Simone was pointing out, the vmtk script computes wall shear rate,
rather than WSS.
It actually does so through its definition (the contraction of the velocity
gradient tensor with the surface normal), by *solely* by performing derivatives
of the velocity field -
Dear Emilie,
1) The pressure field information is usually present in the mesh solution input
file, the script uses it without asking for it.
2) The script computes wall shear rate, if you want wall shear stress you have
to multiply wsr with the viscosity value.
3) The scale depends on the measure
Hello Simone and Evan,
Thank you for your reply.
I tried the function "vmtkmeshwallshearrate", and it seems to work fine. I
get a nice picture, but unfortunately I don't know what am I looking at.
With paraview filters, I tried to approximate the following formula:
The traction vector t is define
Hello vmtk users,
To piggyback on Emilie's query on computing velocity gradients, is
there documentation for either vmtk or Paraview on how they compute
gradients in general for unstructured meshes? For instance, do they
use RBF-FD methods? I couldn't seem to find anything about the
specifics.
Dear Emily,
I think you can use vmtkmeshwallshearrate which computes wsr from a velocity
field.
It supports any kind of mesh files supported by vmtk.
You need to have the velocity array from components (u v w) so you can use
vmtkmeshvectorfromcomponents:
vmtkmeshvectorfromcomponents -ifile input
Dear Luca,
I would like to ask you if there is a way of computing wall shear stress
from nodal velocity and pressure values. In case this is possible, could
you tell me what input file formats are supported?
I'm asking this because the flow solver that I use does not output wall
shear stress. I
