Gauge pressure field started diverging

The Courant number (CFL) exceeded the limit of 1. You may experience either instability or bad temporal accuracy. It is recommended to keep the CFL number below 0.7. In order to achieve this you need to decrease the time step.

Gauge pressure field started diverging. Please check the mesh quality near the reported location and try refining the mesh. If the problem occured near a boundary, please check the boundary conditions. In case of doubt, please ask for assistance via our support chat.
Gauge pressure = -2.17092e+87 at position: (0.4636 m, 0.7783 m, 0.06533 m).

Hi there!

Please always include the link to the project.


I would like to ask you about your boundary conditions, why are you using custom ones? Why did you select such parameters?

This is the link for the reference project which i have been refered for this project.

Link of Reference Project - SimScale

I am not sure of the ‘Fixed flux’ for the pressure field. Also, your BC for the top face is not the same! Please at least make it equal and try again.

Done as you said.

An error with no message has occured.

Link for the project - SimScale

Hi again!

The simulation failing initially could be due to the high Courant number.

Please try to make the following changes under ‘Simulation Control’:

  • Set ‘Adjustable time step’ to True
  • Set a very low Delta t, of around 1e-7

Did as you said…and got this error.


I’d suggest using a hex-dominant instead of a standard mesh for multiphase studies. There should be a handful of articles on this topic.


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Link - SimScale

Did the same previously this are the results.

I have created two seperate volumes one is MFR Zone and a fluid volume. Still the error message dispalys “A multi-region mesh was assigned - this analysis-type requires a single-region mesh.” As this project is for my educational purpose i need to simulate it.
Do take a look at it.
Thank You


I’d suggest searching for the error message, as oftentimes you will find the relevant documentation very quickly :slightly_smiling_face: Rotating regions need to be defined as cell zones.


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