ffc team mailing list archive

[jhoffman@xxxxxxxxxxx]

> On Wed, Aug 31, 2005 at 06:15:43PM +0200, jhoffman@xxxxxxxxxxx wrote:
>
>> No, this is not for the stabilization. It is for applying conditions on
>> surfaces, such as weak boundary conditions. But if we do the assembly
>> over
>> faces, we can take "h" to mean the "face h", so maybe this can remain
>> hidden. But typically we may want to formulate a form including both
>> volume and surface integrals, and then one would like to include an
>> h_face
>> in the surface integral. But as I said; this may be avoided by hiding
>> "h_face" behind the regular "h". On the other hand, we have both dx and
>> ds.
>
> ok, I see your point. We could probably hide it.
>
> Does the h on the face really have to be specific to that face? Is it
> not enough to use the same h (like the diameter)?

I guess it is possible to use the "volume h" as an approximation for "face
h", for now. Although, there could be a significant difference if we have
anisotropic meshes, for example. I have used this in boundary layer
computations, and then the h in one direction could be 10 times (or 100
times) the h in another direction. So we really also would like to be able
to decompose the "volume h" in different directions (h_x,h_y,h_z).

But the first priority now as I see it would be to get the regular "volume
h" = cell diameter to work.

/Johan