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divergence of current density
Posted Aug 10, 2011, 4:49 a.m. EDT RF & Microwave Engineering, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 3.5a 1 Reply
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Hi
I want to find the divergence of current density using the expression div(J) , where J=(epsilonr-epsilon0)E to find the volume charge density (rho) using continuity equation. => div(J) = d/dt(rho)
if I try to find divergence using standard definition of divergence div(J)=(epsilonr-epsilon0)*(d(Ex,x)+d(Ey,y)+d(Ez,z)) I get large values due some numerical error for the finite mesh element size. Is there any other way to find divergence?
Thanks,
Amin
I want to find the divergence of current density using the expression div(J) , where J=(epsilonr-epsilon0)E to find the volume charge density (rho) using continuity equation. => div(J) = d/dt(rho)
if I try to find divergence using standard definition of divergence div(J)=(epsilonr-epsilon0)*(d(Ex,x)+d(Ey,y)+d(Ez,z)) I get large values due some numerical error for the finite mesh element size. Is there any other way to find divergence?
Thanks,
Amin
1 Reply Last Post Aug 13, 2011, 2:00 p.m. EDT
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Posted:
1 decade ago
Hi
have you checked if the Exx Eyy ... are not already defined in COMSOL (I tend to forget how it was back in 3.5 ;), then you do not need to use the div() operator. Also check that you use 2nd or higher shape functions
--
Good luck
Ivar
have you checked if the Exx Eyy ... are not already defined in COMSOL (I tend to forget how it was back in 3.5 ;), then you do not need to use the div() operator. Also check that you use 2nd or higher shape functions
--
Good luck
Ivar