Joule Heating

Hi,

I have started working with Comsol recently and I have been trying to create a model like this: four electrodes in a suspending medium (the model is based in salty water), on a glass surface.
The aim is to create a travelling wave signal so a sinusoidal signal with different phase is applied to each electrode.

I have tried to visualize the temperature after performing a frequency dependent study, but the temperature does not change. Any suggestion to this problem?

I'm trying to upload my model but I still didn't figure it out how to do it.

Thanks.