Hi, I am seeing the following error
In single region simulations, only the fluid region can be assigned to a material. Please review your material assignments, making sure that only the flow volume region is assigned
How to close this error?
Hey there, can you also include the link to your project please? 
Best regards.
Fillia
Please find the link to the model.
Thank you for sharing!
For incompressible analysis cases, you must have a single flow region, the rest of the parts should be assigned as advanced concepts or removed from the model. Additionally, the material can only be assigned to the flow region, not the parts that are assigned as porous media.
Best regards,
Fillia
except inlet and outlet boundaries all go into the advanced concepts you mean?
There are two fluid regions and porous media is sandwitched betwen them if you see the model.
The fluid cylinders that are protruding also need to be part of advanced concept, like rotation with zero radial velocity?
plz suggest
For an incompressible analysis type, only a single flow region should be present. Multiple flow regions that are not connected will not work.
Inlet and outlet boundary conditions are assigned on faces of the flow region.
I gave 3 fluid regions in to one material
i assgined advanced concepts to 4 porous media
inlet to inlet surface of the nozzle and pr outlet to the outer circular surfaces of protruding cylinders.
assigned MRF to all other except porous zones with 0 velocity
but i am not sure why it is showing the same error
In single region simulations, only the fluid region can be assigned to a material. Please review your material assignments, making sure that only the flow volume region is assigned.
plz help to resolve by looking into the model once again
Hi,
The error message is quite straightforward: for the material assignment, only the flow volume should be selected. The other volumes (which are going to be cell zones) should not have any material assigned to them.
Cheers
Oh thanks so much. i was able to get rid of the error but not able to mesh it. Need Help Please.
Error
An error occurred.
What Happened?
A fatal IO (Input/Output) error has occurred while the mesh or the simulation was running.
What Could Be the Possible Reason?
The reason for this error is that the solver has crashed because it could not find a necessary system file.