How to change from dirichlet to newman conditions in a thermal model using PDE?

Hello,

I am using DPE toolbox to simulate the heat conduction between different materials. Once created the model, drawn the geometry and specified the Boundary conditions (ThermalBC) and the material properties I want to change the Boundary conditions to observe the differences but I do not find the way to specify Dirichlet or Newman conditions.

If I create the model using the 'thermal' option (thermalmodelS=createpde('thermal'), the suposed method to do it ( applyBoundaryCondition(thermalmodelS,'dirichlet','Edge',8,'u',200)) is not working. However if I create the model with: "thermalmodelS=createpde " and do not specify 'thermal/structural..." , then, the command "applyBoundaryCondition" works.

How can I select Dirichlet or Newman once having created the Thermal Model?

Thanks for your cooperation.

Answer 1

[Ravi Kumar]

Hi Rubem,

ThermalModel crated using thermalmodelS=createpde('thermal') lets you set up the problem in deomain specific functional interfaces. In thermaBC specifying 'Temperature' is a DirichletBC, all other forms of heat flux, specified using 'HeatFlux', 'ConvectionCoefficient', etc are Neumann BC. You can explore all the methods of thermalmodelS by calling methods(thermalmodelS) in the MATLAB Command Window.

PDE Toolbox also supports general equations based inteface, for which you can craete the analysis model without specifying physics type in the createpde function, like you tried. This model supports mathematical interface for boundary conditions. You can see the methods available for equaiton based using the methods function again.

Regards,

Ravi

Answer 2

[Ruben]

Dear Ravi,

thank you so much for taking your time to reply my question. Now, I understand quite better how it works.

Perhaps you could help me in another issue.

If I set the BC in an edge which is "sandwiched" between two subdomains, the result that I'm having has no sense. With it, I was trying to confirm the result obtained when it was not sandwiched. The new subdomain, above the edge is air and I used a Thermal Conductivity of 0.035 and I was expecting to obtain the same result when not sandwiched. Do you know why?.

Kind regards,

Ruben