[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

# RE: [femm] eddy-curr in a tube

- To: <femm@yahoogroups.com>
- Subject: RE: [femm] eddy-curr in a tube
- From: "McGee" <mcgee@mcmillan-mcgee.com>
- Date: Mon, 9 Apr 2001 21:35:37 -0600
- Importance: Normal
- In-reply-to: <71.c45e762.28013c28@aol.com>

Excellent Presentation of the example. For the boundary conditions, is there a theoretical justification to weight the interpolation values differently to obtain a better answer using finite element. I have developed a FDTD model for my PhD work and I come upon the exact same result you did. Since I was modeled the B and H fields around a particular hysteresis loop it was critically important to ensure that the boundary conditions were properly modeled. In the interpolation of the grid I weighted the interior values more heavily than the exterior values and obtained good results (a 1/3 2/3 rule seemed to work best). Unfortunately I did not have the scope to explore the numerical physics behind the choice of these weighting coefficients. Anyway, I find that your model does a really great job. Any plans to incorporate hysteresis effects.
Bruce

> -----Original Message-----
> From: dcm3c@aol.com [mailto:dcm3c@aol.com]
> Sent: Saturday, April 07, 2001 10:00 PM
> To: femm@yahoogroups.com
> Subject: Re: [femm] eddy-curr in a tube
> In a message dated 4/4/01 10:01:28 AM Eastern Daylight Time,
> rlbrambilla@cesi.it writes:

> > Hi, femm-friends
> > I have a tube of finite length=2L, inner-radius=b,
> > outer radius=a, relative mag. perm.=mur,
> > el. conductivity=sigma.
> > An infinite alternating current line Io.exp(jwt) is positioned
> > (1) on the axis of the tube;
> > (2) parallel to the axis, out at a distance.

D o you know if any analytical
solutions for eddy currents in the tube exist to compare with FEMM analysis?

> Thank you in advance Roberto.
> Roberto Brambilla
> CESI
> Via Rubattino 54
> 20134 Milano
> tel +39.2.2125.5875
> fax +39.2.2125.610
> rlbrambilla@cesi.it

This seemed like it might make an interesting test case. I figured out an
analytical solution for the case where you have a wire carrying AC running
down the bore of a finite length steel tube and compared it to femm's
solution of the same problem. I think this is the same as your case (1).
Check out:
http://members.aol.com/_ht_a/gmagnetics/tube/tube.htm
David Meeker
--
http://members.aol.com/_ht_a/dcm3c
`Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.`

- Follow-Ups:
  - Re: [femm] eddy-curr in a tube
    - From: David Meeker <dmeeker@foster-miller.com>

- References:
  - Re: [femm] eddy-curr in a tube
    - From: dcm3c@aol.com

- Prev by Date: a bit on current amplifiers
- Next by Date: High frequency testing
- Previous by thread: Re: [femm] eddy-curr in a tube
- Next by thread: Re: [femm] eddy-curr in a tube
- Index(es):
  - Date
  - Thread