I need to assign the Neumann-condition on boundary. As Fig.1 shown, what do the q and g mean? If I want to assign that there is no diffusion of ions into or out of the boundary, and the coefficient in PDE as Fig.2 shown. That is right that the g is assigned to be 0 and q is assigned to be '-b*En'? I would be very grateful if you could give me some information about the Neumann-condition.
Hi,
As you know, in Neumann boundary condition, the derivative of your variable is a constant value. If you do the right click on "Coefficient Form of PDE" and add "Flux/Source" then you can sign a constant value for the derivative of the variable. I help it could you.
use livelink MATLAB and obtain the conditions in matlab and apply them for the comsol
Hi,
As you know, in Neumann boundary condition, the derivative of your variable is a constant value. If you do the right click on "Coefficient Form of PDE" and add "Flux/Source" then you can sign a constant value for the derivative of the variable. I help it could you.
Hi,
if you want to define Neumann-condition, you need to setup the g term in Fig. 1. In the q term you setup a Robin-condition, which is dependent of u dof, like admitance, impedance, mechanical spring stiffness, etc.
Method suggested by Vahid Mosallanejad is the right way to do this. g and q are on domain level and cannot be used for applying boundary conditions.
Hello,
What can I create variable boundary condition versus theta for heat transfer two-dimensional polar coordinate steady-state? (for example: T= sin(theta))
Hi, Amir
If you asking How you can create a type of boundary condition that is changing as a function of "teta" or any other variable(like x , y, ...):
My suggestion is to fist make a analytical function f(teta) and name it then put that function in specific part of boundary that you want. I did not practice it but I think is will work, because comsol automatically knows the basic variables like x , y, ..
I hope it can help you.
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