3D diffusion equation in cylinder

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Ahmed Aldohbeyb
Ahmed Aldohbeyb le 29 Mai 2017
Hi everyone, I am new in Matlab and I need some help. I want know if there is a way to solve the PDE for diffusion in a cylinder with 2 cm radius and 10 cm height.
thanks

Réponse acceptée

Precise Simulation
Precise Simulation le 22 Nov 2017
Modifié(e) : Precise Simulation le 22 Nov 2017
Modelling and simulation of convection and diffusion for a 3D cylindrical (and other) domains is possible with the Matlab Finite Element FEM Toolbox , either by using the built-in GUI or as a m-script file as shown below.
% Set up 3D cylindric domain.
fea.sdim = { 'x' 'y' 'z' };
fea.grid = cylgrid( 4, 3, 20, 0.02, 0.1 );
% plotgrid( fea ) % Plot mesh.
% Add covection and diffusion physics mode.
fea = addphys( fea, @convectiondiffusion, {'C'} );
% Define diffusion coefficient.
fea.phys.cd.eqn.coef{2,end} = {'d_coef'};
fea.expr = { 'c', {'1.23'} ;
'd_coef', {'(1+c)^2/((1+c)^2+1)'} };
% Set reaction source term to 1e3.
fea.phys.cd.eqn.coef{6,end} = {1e3};
% Use C = -1 on side boundaries, and insulation
% flux boundary conditions on the top and bottom.
fea.phys.cd.bdr.sel = [ 3 1 1 1 1 3 ];
[fea.phys.cd.bdr.coef{1,end}{2:5}] = deal(-1);
% Check, parse, and solve problem with stationary solver.
fea = parsephys( fea );
fea = parseprob( fea );
fea.sol.u = solvestat( fea );
% Postprocessing.
postplot( fea, 'sliceexpr', 'C' )
title( 'Concentration, C' )
  6 commentaires
Rae K.
Rae K. le 10 Sep 2021
Modifié(e) : Rae K. le 10 Sep 2021
@Precise Simulation The cylgrid function doesn't appear to be part of the Matlab Finite Element FEM Toolbox, or appear anywhere in MATLAB Help/Answers other than this post.
Precise Simulation
Precise Simulation le 5 Nov 2021
The cylgrid function is available as part of the toolbox installation:

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Plus de réponses (1)

Torsten
Torsten le 30 Mai 2017
If you have experience with the discretization of partial differential equations, you can write your own MATLAB code.
Otherwise, I'd suggest you use the PDE toolbox.
Best wishes
Torsten.

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