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Milind Bhowon (mahamil)
New member
Username: mahamil

Post Number: 1
Registered: 11-2006
Posted on Friday, November 24, 2006 - 03:41 am:   

Hello!
I'm quite new to this software and am trying to obtain the temperature distribution of a microwave irradiated biological tissue. I need help with the boundary conditions. Here are the relevant equations and the boundary conditions I have used:

H: dx(H)+dy(H)+eps*dt(E)+sigma*E=0
E: dx(E)+dy(E)+mu*dt(H)=0
Te: div(kc*grad(Te))+omega1*(Tb-Te)+Te*(abs(E))^2=row*cp*dt(Te)

These are the maxwell's equations coupled with the bioheat equation.

I have 2 regions in my model. For the outer region the boundary conditions are fixed, so I have used VALUE boundary conditions.
The problem is with the inner region whose boundary conditions are
K1(dx(E1)+dy(E1))=K2(dx(E2)+dy(E2)) where E1 is the electric field in the outer region and E2 is the field in the inner region. K1 and K2 are conductivities of the two regions. Similar conditions are true for the H field and the temperature Te.
The boundary conditions i have input in FlexPDE are
NATURAL(E)=dx(E)+dy(E)
NATURAL(H)=dx(H)+dy(H)
NATURAL(Te)=normal(kc*grad(Te))
for the second region

I don't think these are the right b.c's. Could you help?
Thanx
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Ravindra Kashyap (kashyapastron)
Member
Username: kashyapastron

Post Number: 8
Registered: 11-2006
Posted on Friday, November 24, 2006 - 05:58 am:   

Hi milind

FlexPDE uses integration by parts to determine the context of the boundary condition specified when "natural" is used and is as such applicable only for PDEs involving second derivatives or higher. There are other threads in this forum where Mr. Nelson has clarified these issues. Please look into them.
I think there you will get what you need.

Bye

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