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Error: Multi-Region Mesh in Non-CHT Simulation

CFD Simulations


A multi-region mesh was assigned ― this analysis type requires a single-region mesh.

CHT Simulations


A single-region mesh was assigned ― this analysis type requires a multi-region mesh.

What Happened?

The meshing process detected multiple solid bodies in the uploaded CAD model for non-CHT simulations.

An opposite error can occur when setting up CHT simulations where the model only has 1 solid body but multiple solid bodies are required.

What Could Be the Possible Reason?

There are multiple bodies in the CAD model. For simulations other than Conjugate Heat Transfer (CHT), multiple bodies are not allowed unless it will be used later under Advanced concepts. However, for some CHT simulations, your model will need to have multiple bodies, otherwise, an opposite error will occur.

What Can I Do Now?

For CFD Simulations (Non-CHT)

If you need multiple bodies for non-CHT simulations, you will need to assign the bodies other than your fluid domain to one of the Advanced concepts available in SimScale which are:

  • Rotating zones: Useful for modeling rotating devices inside the model.
  • Porous media: To model porous media within a CAD geometry reducing meshing efforts.
  • Momentum source: The user will be able to model bodies that generate velocities, such as fans.
  • Passive scalar sources: Important when running passive scalar simulations to track mean age, convection, or diffusion of passive species.
lists of available advanced concepts in simscale that can be used to resolve multiple bodies in non cht simulations
Figure 1: Lists features under Advanced concepts for CFD simulations

For CHT Simulations

An example of when a CHT simulation requires multiple solids is an electronics cooling simulation. This simulation will need the flow region as well as the solid sources that are emitting heat. Having separate bodies will also enable you to define different materials and heat fluxes for each body.

electronics cooling box with multiple solid bodies prepared for a cht simulation.
Figure 2: Example of a model with multiple solid bodies for a CHT simulation

Read more on the preparation of the model for CHT simulations in our How to Prepare the Fluid Region for Conjugate Heat Transfer Simulations? knowledge base article.

Important Information

If none of the above suggestions solved your problem, then please post the issue on our forum or contact us.


Last updated: November 18th, 2020

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