Discussion Forum

Sounds like a multiphysics model to me. Are you modeling magnetohydrodynamics (MHD)? There's a coupled set of magnetic and electric fields (mef) and laminar flow (spf) already available, as suggested for MHD calculations, for you to select within the AC/DC module. I suggest you take a look at that. There's also an example "magnetohydrodynamics pump" model available in the Application Library.

Yes, although the magnetohyderodynamics pump is a stationary solution.

The timescales for EM equations and fluid flow is different. I want to solve EM in frequency domain and fluid flow in time dependent. I should be able to see changing fluid velocities until a user defined termination. I don't know how to get there, for now the example is too simple to provide a time dependent coupling.

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The timescales for EM equations and fluid flow is different. I want to solve EM in frequency domain and fluid flow in time dependent. I should be able to see changing fluid velocities until a user defined termination. I don't know how to get there, for now the example is too simple to provide a time dependent coupling.

You might want to look at RF heating problems, where a frequency-transient study is used to solve the magnetic problem (frequency dependent) and heating (transient).

You may not find an example that is very similar but you may find examples that will give hints on how to approach this.

Thank you. This helped me figure out the problem. Frequency-transient solved the issue. I am trying to add in Heat Transfer as well and I am not sure what coupling interface to use.

Currently I am doing an Electromagnetic Heating interface and coupling magnetic and heat transfer in fluids but the results seem not physically right. The blog page on "Tips and Tricks in Induction Melting" (https://www.comsol.com/blogs/tips-and-tricks-for-modeling-induction-furnaces/) suggests Induction Heating multiphysics between magnetic field and heat transfer in solids. I am not sure if this is right because although it is for modelling induction furnace I am confused as to the usage of heat transfer in solids interface. Is liquid metal still considered as a solid?

The Comsol Help system notes that there are differences in the way heat transfer is represented in the "solids" vs. "fluids" representations. For solids, "the temperature equation defined in solid domains corresponds to the differential form of the Fourier’s law that may contain additional contributions like heat sources," while for liquids, "the temperature equation defined in fluid domains corresponds to the convection-diffusion equation that may contain additional contributions like heat sources." Fortunately, you can find articles available on the internet where various authors discuss their use of heat transfer equations in modeling liquid metals, including in batteries and MHD applications, for example. I suggest you review those carefully and select the approach most appropriate to your particular physical regime of interest. This software provides a wonderful toolbox, but you are the mechanic.