"A setup with at least 28 regions is being used in a single-region analysis type

Hi i currently doing a project to investigate the air flow for emboss shape coolling fin in soalr pv. However, i dont have any clue on how to simulation it using simscale as when i try to simulate it come with message "A setup with at least 28 regions is being used in a single-region analysis type. Please ensure that only one fluid region exists and that all other bodies are assigned to an advanced concept. If you have already meshed your geometry, ensure that all the meshing regions except one are cell zones… Can someone help me. Thank you very much for your coorperation

Hello @bk19110254 ,

Incompressible simulation type requires only one part that will represent the flow region. I assume you are interested in the flow around this geometry, so I would recommend you to create a flow volume first then proceed to delete solid parts. This should do the trick.

I would also strongly recommend you to follow some of the introductory tutorials to make a quick start into SimScale platform.

Hope these are helpful,

tq for the reply…however i still cannot create a flow volume sir… can you help me what problem i did there

Could you please share a link to your project so I can have a better understanding of the CAD model? Thanks!


here Sir, i want to do the flow analysis of emboss fin shape for solar pv cooling

Thanks for sharing!

First, you need to use the Imprint operation in the CAD mode. This will remove the surface discontinuity between fins and main box by splitting faces in contact accordingly.

Secondly, you should also select these side faces of the fins as boundary faces while creating the internal flow volume since they will be bounding the fluid region as well.

Just a side note, simulation type you need could be Conjugate Heat Transfer instead of Incompressible assuming you will be interested in heat transfer between fluid and solid, and heat transfer inside the solid parts as well. Please note that my previous suggestion of removing solid parts after generating the flow volume is not necessary (not valid actually) for conjugate heat transfer simulation. You will need the solids in this case.

Hope these are helpful,

is this the correct imprint Sir ?

Yes, although imprint operation doesn’t require any face/volume selection.

Boundary face selection is valid only for internal flow volume operation, and please make sure that only the faces that are bounding the flow region are selected, not the inner faces. Any one of the inner faces can be selected as the seed face in this case.

Another document that may be helpful:


so after i apply the imprint, i did the boundary faces

is this correct sir?

Not exactly. 2 large faces of the enclosure and 26 side faces of the fins should be selected as Boundary Faces. This selection should be done on both sides of the geometry. So there should be 56 faces selected as boundary and one seed face inside.

Seed face can be any face inside the flow region, please make sure to refer to the previous documentation for more information on seed face selection.


ooh i see, so for the seed face, i chose the correct one right?..only the boundary faces i need to add more?

is this the correct boundary faces sir?

In the very first screenshot that you have shared, yes that’s one of the correct options for the seed face. What I did as follows:

For the seed face, I chose this one:

For the boundary, all these faces on both sides (56 of them) of the geometry should be selected so that these faces will cover the outer boundaries of the flow region:

This will yield to a succesful internal flow volume generation. Hope these are helpful,


now i get it thank you very much sir for your help

1 Like

however, sir my project is to study the flow behaviour around the fin…isnt that incompressible simulation is suitable?

In case you are only interested in the flow behaviour, Incompressible simulation type is the correct approach. However, temperature dependent effects are not taken into account in Incompressible simulations such as free convection in air. (No heat transfer)

In case you are only interested in the flow behaviour along with temperature effects inside the air, you should go with a convective heat transfer simulation. (Heat transfer only inside the fluid)

Conjugate Heat Transfer simulations should be used to simulate the heat exchange between the fluid and solid parts. (Heat transfer inside the fluid and solid).

Please make sure to refer documentation page for more information on simulation types.

ooh i see so if like that , it is better for me to go for conjugate heat transfer right…since i want to analyse the effect of embossed shape fin (solid) on the temperature of solar panel

if i use convective heat transfer, i could not get the temperature of the solar panel right

I would say conjugate heat transfer is the most commonly used simulation type in electronics cooling application.

You may want to follow this particular tutorial on electronics cooling by using conjugate heat transfer simulation. Step-by-step descriptions can be easily adapted to your own application.


alright Sir, thank you so much for your help without your guidance, i could not settle this problem related to my project. Good bless you Sir