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<DIV><FONT size=4 face=Calibri><STRONG><U>Background</U></STRONG> </FONT></DIV>
<DIV><FONT size=4 face=Calibri></FONT><FONT size=4
face=Calibri></FONT> </DIV>
<DIV><FONT size=4 face=Calibri>I am doing Finite Element Analysis to study the
flow of electric current in persons and animals due to stray electric current in
bodies of water. I am using FEAtool(a MATLAB plugin) which employs gmsh to
generate grids from geometries. </FONT></DIV>
<DIV><FONT size=4 face=Calibri></FONT> </DIV>
<DIV><FONT size=4 face=Calibri>Part of my analysis involves the calculation of
the total current through (perpendicular to) the cross section of a sub-domain
which is bordered by the intersection of a cut plane and the subdomain surface.
This current is the integral of current density over the area of the cross
section. </FONT></DIV>
<DIV><FONT size=4 face=Calibri></FONT> </DIV>
<DIV><FONT size=4 face=Calibri>FEAtool does this integration but <U>only over a
surface that is a boundary of the subdomain</U>.</FONT></DIV>
<DIV><FONT size=4 face=Calibri></FONT> </DIV>
<DIV><FONT size=4 face=Calibri>Here is an example (See attached
illustrations.):</FONT></DIV>
<DIV><FONT size=4 face=Calibri></FONT> </DIV>
<DIV><FONT size=4 face=Calibri><U>Geometry</U>: a 1m cube (subdomain 2)
containing a component (subdomain 1) made of 4 joined cylindrical sections.
</FONT></DIV>
<DIV><FONT size=4 face=Calibri></FONT> </DIV>
<DIV><FONT size=4 face=Calibri><U>Boundaries</U>: 5V/0V on the opposite faces of
the cube that are perpendicular to the axes of the cylinders and zero current on
the other cube faces.</FONT></DIV>
<DIV><FONT size=4 face=Calibri></FONT> </DIV>
<DIV><FONT size=4 face=Calibri><U>Solution</U>: current density is plotted and a
YZ plane is cut through it in the center (at x = 0.5).</FONT></DIV>
<DIV> </DIV>
<DIV><FONT size=4 face=Calibri>I want to calculate the current flowing through
each of the small connecting cylinders by integrating the current density over
the two circular, planar intersections of the cut plane and the two small
cylinders.</FONT></DIV>
<DIV><FONT size=4 face=Calibri></FONT> </DIV>
<DIV><FONT size=4 face=Calibri>In order to do this wholly within FEAtool, I must
create (geometry) the small cylinders so that they are in two pieces and simply
share a face/boundary. That way there is a pre-defined <U>boundary over
which FEAtool can do the integration</U>.</FONT></DIV>
<DIV><FONT size=4 face=Calibri></FONT> </DIV>
<DIV><FONT size=4 face=Calibri>Sometimes this is not possible/convenient because
the model geometry has been imported and/or is quite complex (such as that of a
human body) or because the decision to make such a measurement/cut-plane is made
only after the model and mesh is completed and the solution is being
examined.</FONT></DIV>
<DIV><FONT size=4 face=Calibri></FONT> </DIV>
<DIV><FONT size=4 face=Calibri><STRONG><U>Question</U></STRONG></FONT></DIV>
<DIV><FONT size=4 face=Calibri></FONT> </DIV>
<DIV><FONT size=4 face=Calibri><U>If I export the model geometry and/or the mesh
from FEAtool to gmsh can the model/mesh be split by a designated plane within
gmsh so that, when exported and imported back into FEAtool, the sub-domains
intersected by the plane would have true faces/boundaries so they could be
designated in an integration?</U></FONT></DIV>
<DIV><FONT size=4 face=Calibri></FONT> </DIV>
<DIV><FONT size=4 face=Calibri>If possible, but not required, I would like to be
able to designate the sub-domains to be split by the cut plane in gmsh so as to
not split a sub-domain over which integration is not needed.</FONT></DIV>
<DIV><FONT size=4 face=Calibri></FONT> </DIV>
<DIV><FONT size=4 face=Calibri>From the FEAtool perspective, see: </FONT><A
style="href: "
href="http://forum.featool.com/Integration-of-Current-Density-over-Slice-Intersection-td180.html"
integration-of-current-density-over-slice-intersection-td180.html??
forum.featool.com http:><FONT size=4
face=Calibri>http://forum.featool.com/Integration-of-Current-Density-over-Slice-Intersection-td180.html</FONT></A></DIV>
<DIV><FONT size=4 face=Calibri></FONT> </DIV>
<DIV><FONT size=4 face=Calibri>Kind regards,</FONT></DIV>
<DIV><FONT size=4 face=Calibri>Randal</FONT></DIV>
<DIV><FONT size=4 face=Calibri></FONT> </DIV>
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