Using Matlab for solving 3d PDE and creating geometry

Question

amit amit 2018-12-10

编辑： Ravi Kumar 2024-5-1

Hi I need to solve a 3D diffusion equation on a geometry of a sphere inside a cube.

However - I saw that in PDE toolbox I can only create a sphere inside a sphere or a cube inside a cube. Therefore I would like to ask:

How can I create this kind of geometry?
How would I then manage the boundary conditions?
What is the right syntax for coefficient speficiation in 3D (speficially here the sphere is a source and the cube has no source)?

Thanks.

sevgi 2024-3-7

hello, I have a similar problem. did you find a solution

Answer 1

Ravi Kumar 2024-4-30

编辑：Ravi Kumar 2024-5-1

Here is an example.

gmCube = fegeometry(multicuboid(1,1,1));

gmCube = gmCube.translate([0,0,-0.5]); % Translate so that the cube is centered at the origin.

gmSphere = fegeometry(multisphere(0.25));

gmSphereInCube = addCell(gmCube,gmSphere);

pdegplot(gmSphereInCube,'CellLabels','on','FaceAlpha',0.5)

If you are using MATLAB R2022b or older, then skip the fegeometry() calls.