COMSOL Forums: How to set boundary conditions from parametric solver

Re: How to set boundary conditions from parametric solver

Mon, 15 Mar 2010 10:07:28 +0000

Hello

We have understood how define the parameters of the solver to associate as boundary conditions as parameters. For example, if we take param1=1 param2=0 param3=-1, we can fix a current entering on a first border, an electric insulation on the second and an outgoing current on the third. Thus, the problem will be solved for these boundary conditions. If we add three new values in the window parameter value, Comsol will start up a second resolution, ect…
But in our case, we would wish to associate a set of 1064 boundary conditions (or less if we are able to group them by function: current entering, outgoing, insulation…)with only one value parameter. For that, parameter would be the number of a line of matrix made up of 1064 values. These data could be in an additional file that we call in the window parameter sweep or could be generated by a function connecting a number of parameter has a set of number of border.

It is this passage which we do not manage to format in Comsol.

Thanks for your help!

Re: How to set boundary conditions from parametric solver

Fri, 12 Mar 2010 19:55:08 +0000

Hi

My way (there are many) is to define a variable "param" as range(0,0.1,1) (typically from 0 to 1) and then I multiply the amplitude of my signal by "*param".

So if you have several electrodes, and you have grouped them into a "group" you can define a BC (boundary condition) as Voltage = Vamplitude*param (Vamplitude being defined i.e. in the Constants as Vamplitude = 10[V] or whateverfits you) and normally off you go

But you can also define the parameter directly as a voltage value, just check the units, as noramlly the parameter is unitless

And when thing fails, try it out on the simplest model you can imagine, to learn the principle behind, one often fails because of the complexity of the multiphysics, its not always just to jump in and "play winner"

Good luck
Ivar

How to set boundary conditions from parametric solver

Fri, 12 Mar 2010 13:28:07 +0000

hello,

We want to successivly run a DC_model by changing only some boundary conditions (i.e. current density on a face) on only some geometric objects (i.e. electrods).
We want to use parametric solver to perform this operation. For that:
We tried to group together boundaries in Options/Boundary Expressions and linked them to a variable. This variable was defined in Options/Constant as a value of current density. In the menu Solve/parametric sweep, we typed in the window "parametric name" the group name of the boundaries we want to change value. In the window "parametric value" we typed the constant name which represents the value of current density.
But it doesn't work! help!!

Thanks for your help