[ryaanamank]

I am getting an error in my simulation: ´time-step limit =dt_min forced by temperature extrapolation error´ can anyone please tell me why is it so? and what should I look into in order to rectify it.

Thanks in advance

[alemoine]

Hi ryaanamank,

The error "time-step limit =dt_min forced by temperature extrapolation error" occurs when one of the equations does not converge. To diagnosis this issue, you will need to look at the convergence of the equations to get a better sense of what is leading to this crash.

The first step would be to activate the most detailed screen output. For CONVERGE v2.3, go to Case Setup < Simulation Parameters < Run Parameters < Misc < Screen print level and select "Verbose" from the drop-down menu. Similarly you can go into the inputs.in file and set screen_print_level = 2. While the simulation is running, it will print out additional information to the screen about the convergence of each equation being solved.

Next you will want to rerun your simulation to replicate the crash and store the screen output. If you are using a restart file, use an older restart file. The most recent restart file may already contain some solution instabilities and will not help in the debugging process.

After you are able to replicate the crash, take a look at the screen output. Focus on looking at the residuals of the equations. Are any of the residuals increasing over time or oscillating? Which equation do these aforementioned instabilities occur (pressure, energy, etc.). Take note of the time you notice this happening. Are there any physical models that are activated during this time? As an example, if the solution becomes unstable during spray injection, then perhaps you need to reexamine the grid resolution around the spray.

In order to help debug this issue, you will need to provide some additional information.

Best,