[Gmsh] Stacked Extrusions

[Laird Bolt]

Hello:

I was hoping that someone could please explain the best way to stack extruded surfaces.

Consider the simple example of a smaller rectangular block stacked ontop of a larger
rectangular block.

To build it I can simply draw the footprint of the larger block and extrude it vertically.
I can then draw the second (smaller block) and extrude it vertically.  Although the
.pro files do not show it the intent in the future is for the blocks to be dissimilar materials
and the design far more complex whick will make extruding the complex shape from the base
very difficult.

THis simple test case draws correctly as seen in GMSH.  However when I solve it using GETDP
I find that the two blocks are not seen to be connected.

I do not find this surprising but I can not figure the correct way to fuse the two surfaces. <<cube1.pro>>  <<thermal.pro>> 

Interestingly I have (on a non-repeatable basis) had success if the extrusion are directed
toward each other.

I have attached the .pro files for information but I suspect that the problem is my incorrect
specification in the .GEO.

The geo File is:

Point(1) = {-0.002, 0.00, 0.000, 0.0005};
Point(2) = {0.0, 0.002, 0.000, 0.0005};
Point(3) = {0.002, 0.00, 0.000, 0.0005};
Point(4) = {0.0, -0.002, 0.000, 0.0005};
Point(9) = {-0.001, 0.00, 0.004, 0.0005};
Point(10) = {0.0, 0.001, 0.004, 0.0005};
Point(11) = {0.001, 0.00, 0.004, 0.0005};
Point(12) = {0.0, -0.001, 0.004, 0.0005};

Line(1) = {1,2};
Line(2) = {2,3};
Line(3) = {3,4};
Line(4) = {4,1};
Line Loop(13) = {1,2,3,4};
Line(19) = {9,10};
Line(20) = {10,11};
Line(21) = {11,12};
Line(22) = {12,9};
Line Loop(23) = {19,20,21,22};
Plane Surface(30) = {13};
Plane Surface(36) = {23};

Extrude {0,0,0.004} {Surface{30}; Recombine; Layers{{10},{2000},{1}};}
Extrude {0,0,0.004} {Surface{36}; Recombine; Layers{{10},{2001},{1}};}

//Physical Line used to add Convection Boundary Condition
Physical Surface(1000) = {30};

//Physical Line used to Add Flux Boundary Condition
Physical Surface(1001) = {80};

//Physical Surface used to represent the Bar
Physical Volume(100) = {2000};
Physical Volume(101) = {2001};


Thankyou

Laird Bolt

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