Irregular surface and Gmsh2D

[Fausto Arinos de A. Barbuto]

Hi,

Is it OK to define the contour of an irregular shape based on its (X,Y)

coordinates only, e.g.:

    X, Y = mesh.faceCenters

    L1 = (X == 0.000) & (Y <= 0.025)

    L2 = (X == 0.025) & (Y >= 0.025)

    T1 = (X <= 0.025) & (Y == 0.025)

    T2 = (X >= 0.025) & (Y == 0.200)

    B1 = (X <= 0.300) & (Y == 0.000)

    B2 = (X >= 0.300) & (Y == 0.050)

    R1 = (X == 0.300) & (Y <= 0.050)

    R2 = (X == 0.500) & (Y >= 0.050)

that is, without caring about mesh.facesLeft, mesh.facesBottom etc? I 

find it easier (albeit sillier, too) this way, sometimes.

A comment about FiPy's mesh generator function Gmsh2D. It allows one to 

define line labels such as:

Physical Line("L1") = {8};

Physical Line("B1") = {1};

Physical Line("B2") = {3};

...

Yet I wasn't able to use those line label definitions directly, like:

    phi = CellVariable(name="phi(x,y)", mesh=mesh, value=0.0, hasOld=True)

    phi.constrain(10.0, L1)

    phi.constrain(0.0, L2)

    phi.faceGrad.constrain(0.0, R1)

and so on and so forth? Do I still have to define the contour as shown 

at the beginning of this message? I get error messages saying that L1,

L2, etc, weren't defined.

Thanks,

Fausto

[Guyer, Jonathan E. Dr. (Fed)]

On Jan 28, 2021, at 2:45 PM, 'Fausto Arinos de A. Barbuto' via fipy <fi...@list.nist.gov> wrote:

Hi,

Is it OK to define the contour of an irregular shape based on its (X,Y)

coordinates only, e.g.:

    X, Y = mesh.faceCenters

    L1 = (X == 0.000) & (Y <= 0.025)

    L2 = (X == 0.025) & (Y >= 0.025)

    T1 = (X <= 0.025) & (Y == 0.025)

    T2 = (X >= 0.025) & (Y == 0.200)

    B1 = (X <= 0.300) & (Y == 0.000)

    B2 = (X >= 0.300) & (Y == 0.050)

    R1 = (X == 0.300) & (Y <= 0.050)

    R2 = (X == 0.500) & (Y >= 0.050)

that is, without caring about mesh.facesLeft, mesh.facesBottom etc? I 

find it easier (albeit sillier, too) this way, sometimes.

You absolutely can do this. Internally, that’s all that FiPy is doing, e.g.,

  https://github.com/usnistgov/fipy/blob/master/fipy/meshes/abstractMesh.py#L789

A comment about FiPy's mesh generator function Gmsh2D. It allows one to 

define line labels such as:

Physical Line("L1") = {8};

Physical Line("B1") = {1};

Physical Line("B2") = {3};

...

Yet I wasn't able to use those line label definitions directly, like:

    phi = CellVariable(name="phi(x,y)", mesh=mesh, value=0.0, hasOld=True)

    phi.constrain(10.0, L1)

    phi.constrain(0.0, L2)

    phi.faceGrad.constrain(0.0, R1)

and so on and so forth? Do I still have to define the contour as shown 

at the beginning of this message? I get error messages saying that L1,

L2, etc, weren't defined.

You need to write:

    phi.constrain(10.0, mesh.physicalFaces["L1"])

    phi.constrain(0.0, mesh.physicalFaces["L2"])

    phi.faceGrad.constrain(0.0, mesh.physicalFaces["R1"])

See the example at

https://www.ctcms.nist.gov/fipy/fipy/generated/fipy.meshes.html#module-fipy.meshes.gmshMesh

[Fausto Arinos de A. Barbuto]

On Thursday, January 28, 2021, 07:46:53 p.m. GMT-3, 'Guyer, Jonathan E. Dr. (Fed)' via fipy <fi...@list.nist.gov> wrote:

> You need to write:

    phi.constrain(10.0, mesh.physicalFaces["L1"])

    phi.constrain(0.0, mesh.physicalFaces["L2"])

    phi.faceGrad.constrain(0.0, mesh.physicalFaces["R1"])

> See the example at

> https://www.ctcms.nist.gov/fipy/fipy/generated/fipy.meshes.html#module-fipy.meshes.gmshMesh

Thanks. I tried mesh.L1 and it obviously didn't work.

Fausto