SimScale CAE Forum

Help with OpenFOAM meshing


#1

https://www.simscale.com/workbench/?pid=2640120133261621925#tab_1-0

New to SimScale and trying to determine transient state heat transfer between a solid and a particular fluid at their interface for an application. SimScale requires this type of study to use an OpenFOAM mesh and we do not have the expertise to operate in that format. Would someone be able to assist in the conversion of the two simple solids into an OpenFOAM mesh?

Thanks


#2

Hello @iosili,

Welcome to SimScale. :slight_smile:

I see that your geometry has two cylinders - a good place to start would be to know the simulation setup. Could you describe the boundary conditions on the geometry?


#3

Hello @sjoshi,

Thanks for your response. Smaller disc (top) is transient heat source. It is in open air and is subject to heat loss through convection from its top and sides, and through conduction at interface with bottom disc. Larger disc (bottom) will have its sides and bottom encased and will theoretically have no energy heat loss or heat gain except at top surface where it interfaces directly with top disc or through convection from area not interfacing with top disc. Does this help?

Thanks


#4

@iosili, since the simulation involves multiple domains with different material properties, you should create a multi-region mesh. However, the geometry is still missing the region occupied by air. I would suggest you to modify the geometry in the following way:

  1. Open your geometry in a CAD modeler of your choice (e.g. Onshape)
  2. Create a box that occupies the region where airflow occurs.
  3. From this box, subtract the other geometry entities - at the end of this step, you will have three disjoint regions: air, the smaller disc and the larger disc. These three regions share some boundaries with each other.

Upload this geometry to SimScale, and follow this link for more information on how to generate a multi-region mesh.

Please let me know if you have more questions or issues.


#5

Thanks very much. I am having issues with Simulation Control settings. I want a simulated run of 20 minutes with recordings every 15 seconds. What is the correct setting for this?
Thanks


#6

Hi @iosili,

you can set the End time value [s] to 1200 and the Write interval to 80 meaning that we will write out every 80th timestep which is equal to approx. 15s.

Important hint: For a “Steady-State” analysis Time step length is a ‘pseudo’ time-step and holds no physical meaning. It simply determines the “Number of Overall Iterations” done to reach a steady-state, calculated as “(End time) / (Time step length)”.

Best,

Jousef