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Hello everyone! I'm a newbie to COMSOL. Unfortunately, I'm experiencing some difficulty in trying to model a relatively simple problem in COMSOL, and I'd be really really thankful if anyone could help me out. Let me cut to the chase. I was tasked with modelling a cuboidal container with a diaphragm on top. The diaphragm is the ceiling of the container (with a finite thickness of course). Now, a Piezoelectric material (a cuboidal strip of finite thickness) is supposed to be attached to the top of the diaphragm (ceiling). In theory, when a voltage is applied to the surface of a piezoelectric material, it deforms. My task was to make it such that the diaphragm deflected downwards. So through trial and error, I found that the voltage must be applied at the top surface of the Piezoelectric material. Moving on, the container is filled with a fluid (say water or ink). (This is supposed to be a really primitive version of a Piezoelectric inkjet printhead WITHOUT THE NOZZLE :p). There is no inlet or outlet. The deflection of the diaphragm, theoretically, causes a change in pressure of the fluid which I am supposed to measure. This is the part where I'm stuck. How do I fill fluid in the container? Which physics should I use for this problem? I tried modelling a solid cuboid and assigned it to "water" and made the diaphragm and piezo material on top? But then what boundary conditions should I give for the fluid physics that I use? (say laminar flow) Should I couple a fluid physics at all? If I don't use a fluid physics, it asks me for the coupling matrix and elasticity matrix for water, both of which I couldn't find out. If I couple a fluid physics with piezoelectric physics then, I do not know what boundary conditions to give for the fluid. I'd really appreciate it if someone could help me out with this. I'll post an image file for reference. I can't upload the model though (my university net restricts me from uploading files of sizes larger than 1MB :( ) Downloads are allowed though, so if you can make a similar model with the necessary changes and upload it, that'd be great! But general instructions and advice are also really welcome and would be highly appreciated. Also keep in mind that I'm a newbie to COMSOL. Thanks in advance!
