Information about meshgrid in pdetool. How can I define specific mesh?

Hello, I am developing a project to study a heat transfer in a plate. I am using pdetool to solve the EDP.

I would like to know a little bit more about the mesh...

Now, I have this mesh:

But I would like the mesh like squares:

Is it possible?

Cheers

Answer 1

[Ravi Kumar]

Hi Yogan,

PDE Toolbox does not support quadrilateral elements as shown in your second picture. If your purpose is the find the solution on a rectangular grid, then you can first solve using the PDE Toolbox triangular mesh and then interpolate the solution onto a rectangular grid. Refer to the documentation following documentation page for examples:

https://www.mathworks.com/help/pde/ug/pde.steadystatethermalresults.interpolatetemperature.html

Also, I would suggest use the programmatic approach as shown in the documentation not the PDE App.

Answer 2

[Precise Simulation]

If you prefer to set up and solve heat transfer plate and other PDE problems with a structured quadrilateral mesh, it is possible to use the rectgrid function included in the finite element FEA toolbox . The following code shows a small example of defining and solving heat conduction in a rectangular 2D domain with structured quadrilateral mesh cells (alternatively, you can use the GUI at first, and then save you model as an editable m-file script file to see how the FEA script modeling and definition works):

    % Define geometry and grid.
    nx  = 20;
    ny  = 5;
    dim = [ 0, 4; 0, 1 ];
    fea.grid = rectgrid( nx, ny, dim );
    fea.sdim = { 'x' 'y' };

    % Add heattransfer multiphysics mode.
    fea = addphys( fea, @heattransfer );
    rho = 1;
    k   = '1e-3*(1 + x)';
    cp  = 'cos(x)';
    fea.phys.ht.eqn.coef{1,end} = { rho };
    fea.phys.ht.eqn.coef{2,end} = { cp };
    fea.phys.ht.eqn.coef{3,end} = { k };

    % Use temperature boundary conditions (1)
    % on the left (4) and right (2) edges.
    fea.phys.ht.bdr.sel([2 4]) = 1;   
    Tl  = 300;
    Tr  = 450;
    fea.phys.ht.bdr.coef{1,end}{2} = Tr; 
    fea.phys.ht.bdr.coef{1,end}{4} = Tl; 

    % Check, parse, and solve stationary problem. 
    fea = parsephys( fea );
    fea = parseprob( fea );
    fea.sol.u = solvestat( fea );

    % Plot grid and solution.
    postplot( fea, 'surfexpr', 'T', 'linestyle', '-' )