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Electric Field BC
Posted 21.02.2012, 04:57 GMT-5 5 Replies
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Hi,
I'm a new user to comsol and I am trying to model an active micromixer combining Fluid Flow, Transport of Diluted Species and AC/DC modules. In this sproblem, I have Electric Field boundary conditions at the two inlets. This electric field comprises an AC plus a DC term (Edc+Eac*sin(omega*t)). I want to define this BC on two inlets and obtain the resultant Electric field in the whole domain. In most micromixers there is some potentials defined on some boundaries and defining this type is quite easy in COMSOL. However, I couldn't find any BC type to define electric field itself, instead of potentials. How can I define this BC?
Thank You.
I'm a new user to comsol and I am trying to model an active micromixer combining Fluid Flow, Transport of Diluted Species and AC/DC modules. In this sproblem, I have Electric Field boundary conditions at the two inlets. This electric field comprises an AC plus a DC term (Edc+Eac*sin(omega*t)). I want to define this BC on two inlets and obtain the resultant Electric field in the whole domain. In most micromixers there is some potentials defined on some boundaries and defining this type is quite easy in COMSOL. However, I couldn't find any BC type to define electric field itself, instead of potentials. How can I define this BC?
Thank You.
5 Replies Last Post 21.02.2012, 10:35 GMT-5
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Posted:
1 decade ago
Hi
Quite a challenging project ! may I come with a suggestion, if you are a newbeginner with COMSOL, to learn all the notation in use, start "simple" that is one physics at the time, solve them independently so far that is possible, then add two, and three etc. Jumping in the bath with all physics floating around is rather confusing, at least the first time, And I would add even after 3 years with COMSOLING ... :)
But it's great fun
--
Good luck, and have fun COMSOLing
Ivar
Quite a challenging project ! may I come with a suggestion, if you are a newbeginner with COMSOL, to learn all the notation in use, start "simple" that is one physics at the time, solve them independently so far that is possible, then add two, and three etc. Jumping in the bath with all physics floating around is rather confusing, at least the first time, And I would add even after 3 years with COMSOLING ... :)
But it's great fun
--
Good luck, and have fun COMSOLing
Ivar
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Posted:
1 decade ago
I am wondering whether defining an electric field distribution can be a sufficient boundary condition from a principal standpoint. One could always add a constant potential without changing the field?
And how would a field distribution be realized in a real world device?
Cheers
Edgar
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Posted:
1 decade ago
Ivar,
Thank you for your comment. I've found you a very active member in discussions. Such an energy is admirable and I envy you a bit! :)
OK. Just think that I'm modeling a single physics and I only want to gain the distribution of electric field within a domain, but some of my boundaries are electric fields instead of potentials. Then, what should I do? What's your suggestion?
Edgar,
That's a good point. I wondered about it myself. However, since I have found this problem in a scientific paper and the authors have mentioned that this is their boundary condition at inlets, I think that it should be sufficient [?]. The fact is that I'm a mechanical engineer and I'm not good enough with all these electric stuff! BTW, I'm attaching an image of the geometry under consideration (taken from that article) for your perusal.
Thanx again.
Thank you for your comment. I've found you a very active member in discussions. Such an energy is admirable and I envy you a bit! :)
OK. Just think that I'm modeling a single physics and I only want to gain the distribution of electric field within a domain, but some of my boundaries are electric fields instead of potentials. Then, what should I do? What's your suggestion?
Edgar,
That's a good point. I wondered about it myself. However, since I have found this problem in a scientific paper and the authors have mentioned that this is their boundary condition at inlets, I think that it should be sufficient [?]. The fact is that I'm a mechanical engineer and I'm not good enough with all these electric stuff! BTW, I'm attaching an image of the geometry under consideration (taken from that article) for your perusal.
Thanx again.
Attachments:
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Posted:
1 decade ago
Mohammad,
are you sure the authors are really refering to electrical field strength? Many publications are inaccurate in units and wording. Field strength is a vector, so it must be given in components. And it wouldn't be a single value or vector value in such a complex geometry. It would be a vector field, depending on the spatial coordinates. Is the value given in V/m or in V?
Check the paper for plausibility.
Cheers
Edgar
are you sure the authors are really refering to electrical field strength? Many publications are inaccurate in units and wording. Field strength is a vector, so it must be given in components. And it wouldn't be a single value or vector value in such a complex geometry. It would be a vector field, depending on the spatial coordinates. Is the value given in V/m or in V?
Check the paper for plausibility.
Cheers
Edgar
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Posted:
1 decade ago
Edgar,
Thank you for your remarks. You are right. However I have checked the units and they are [V/cm]. Thus, they are electric fields. But your comment motivated me to read again some parts of the paper and I realized that the authors are talking about both voltage and electric fields! In fact, their discussion about electrical BCs seems vague and a bit messy! I'm going to contact them and ask about it. Hope they reply!
I will get back to the topic as soon as I come to a conclusion.
Regards
Thank you for your remarks. You are right. However I have checked the units and they are [V/cm]. Thus, they are electric fields. But your comment motivated me to read again some parts of the paper and I realized that the authors are talking about both voltage and electric fields! In fact, their discussion about electrical BCs seems vague and a bit messy! I'm going to contact them and ask about it. Hope they reply!
I will get back to the topic as soon as I come to a conclusion.
Regards