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Hi,

I am trying to solve a transient heat diffusion model which employs a user-defined function for thermal conductivity (k) of a particular sub-domain in the geometry. This user defined function is written in MATLAB and depends on the space co-ordinate variables x and y as well as the dependent variable T (i.e. temperature). This function cannot be expressed in analytic form. Now, I created a mapped mesh in COMSOL and projected the temperature (T) values from these mesh nodes onto a finer mesh made in Matlab using the 2D interpolate function called 'interp2' (This finer mesh in Matlab is essential to calculate my user-defined thermal conductivity function). However I was not able to perform this interpolation since I found that the values of the space coordinates x and y vary with every iteration (from time t=0 to time t=tfinal) and in actuality are not the same as the x and y coordinates of the mesh nodes. I thought that the space coordinates of a sub domain correspond to the mesh nodes in that sub-domain and will remain fixed from time t=0 to time t=tfinal. Unfortunately it is not so and hence I am not able to perform the 2D interpolation (since both the size of x (and y) as well as the values of x (and y) change over time). Can anyone please let me know of a way to get around this problem?

Thank you very much.
Archana