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ERT- Boundary conditions

Fazlul Rahman Mohd Yunus

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Hi,
I have a circular pipe filled with liquid (sig1=0.3S/m) with diameter of 100mm and at internal wall of the pipeline and I placed 16 steel electrodes to measure surface potential when I injected current (10mA) using the opposite excitation. The objective is to construct slice image from the sets of measurements on surface potential when resistivity changes in presence of gas bubble in the pipe. I apply the poisson's equation and dirichlet boundary condition as shown in the attachment. In the model I used two physics which are electric current(ec) and PDE. Settings which has been done are as follows:
Electric current (ec)
terminal 1= 10mA terminal 2= -10mA
terminal type : current terminal type= current

PDE (c)
Dependant variable qty : electric field (V/m)
Source term qty : current source (A/m^2)

Coefficient form PDE
c=-0.33 (s^3A^2/mkg)
others coefficient =0

Drichlet boundary condition1 (source)
r= ec.normJ/sig1 (V/m)

Drichlet boundary condition2 (sink)
r=-ec.normJ/sig1 (V/m)

Dirichlet boundary condition3 (others)
r=0

I am in a doubt and I would like to know if the settings in COMSOL has fullfilled the attached equation?

Regards
Fazlul


0 Replies Last Post 30.06.2014, 04:05 GMT-4
COMSOL Moderator

Hello Fazlul Rahman Mohd Yunus

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