[Gmsh] [mark.starnes at fttech.co.uk: Re: Mesh size definition referring to surface or volumenumbers.]]

[Mark Starnes]

On Fri, May 27, 2011 at 11:30:14AM +0100, Geordie McBain wrote:
> 2011/5/26 Mark Starnes <mark.starnes at fttech.co.uk>:
> > Hi Geordie, ?thanks for the rapid reply.
> >
> > Your example helped a great deal. ?Thanks!
> > I went on with it, attempting to define the
> > field for more than one surface, using MathEval
> > to set the mesh size for an initial field, then
> > defined a new second field for each surface using
> > Restrict (following your example).
> >
> > Can you tell me how to combine these field
> > definitions, please? ?I tried Min, Max, MathEval
> > and MinAniso types to define my last field
> > (referenced as the background field) but the
> > element sizes in different regions all appear the
> > same.
> >
> > I have attached my efforts (for what they are worth).
> 
> Hmm.  I get a good result with your third option, MinAniso.  Indeed I
> get the similar good result with Min, but you only want to apply Min
> to the three Restricted fields {4, 5, 6}, not the constant fields {1,
> 2, 3}.  I attach my version of your .geo file, with your third option
> uncommented, and then a picture of the mesh I get with "gmsh -2
> minaniso.geo".
> 
> Actually this is a terrible mesh, but I assume that's beside the point
> at the moment.

Hi again, Geordie and more thanks for your time.

I ran your geometry here and it works;  I don't
know why it didn't the first time.  Thanks for
having a look.

I have two last questions, if you don't mind.
First, my impression is that if all Points used
to define a volume have a characteristic length
smaller than that described by a field applied,
the smaller characteristic length will be adopted.
Can this behaviour be changed?  I have an acoustic
volume filling a structural shell and the points
on the shell have small lengths:  this results in
the elements in the acoustic volume becoming small
when I can get away with them being large.

Second, is it possible to define a vector field?
I would like to be able to define a vector field
in my structure, to stretch the generated elements
in one direction relative to the other.

You have been of great help.  Thank you.

Best regards,

Mark.


-- 
Dr. Mark Starnes
Senior Physicist
FT Technologies
Church Lane
Teddington
TW11 8PA

web:  www.fttech.co.uk
DDI:  0208 614 2730

----- End forwarded message -----

-- 
Dr. Mark Starnes
Senior Physicist
FT Technologies
Church Lane
Teddington
TW11 8PA

web:  www.fttech.co.uk
DDI:  0208 614 2730 
  
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