Learning Forum

[rigustafson]

Hi,

I am trying to run a 2D cfd simulation with species transport. I have tried creating a simple geometry with an inlet, outlet, and walls, but I am not seeing the species I want to track inside the fluid domain, nor is the residuals console appearing. Furthermore, when I open Windows Task Manager, it says Fluent is not responding after I try running a calculation. I have used Fluent in the past successfully, so I don't know what I am missing now. I am using the 2020 R2 student version downloaded from the Ansys website. I want to run in serial mode, because my node count is pretty small.

[Rahul Kumar]

Hello,
May I know which species model you are using? If you turn off species, does the simulation run fine?

[rigustafson]

I am using the default species (H2O, O2, N2) for a mixture and only inject 0.1 mol% of H2O with N2 as the balance. I also tried running without using the species model, but the lack of a residual console plot and "not responding" error persisted. I had changed all the convergence levels to 1e-6, too. The solver kinda hangs for a bit without a console window appearing, but after some time, the simulation completes and I am able to view the flow field. The flow patterns appear correct, but I cannot observe species transport nor how the residuals are converging.
Thank you for your reply. Any thoughts?

[rigustafson]

* without a residual console plot appearing *

[Rahul Kumar]

Please check if your hardware is as per the recommended settings to use Fluent.

[rigustafson]

My machine specs are: intel i7-10700 @ 2.9 GHz base, 8 cores, 64 GB of DDR4 RAM. I have run ANSYS Fluent 2020 R2 last year with the student license fine. When I reopen an old .cas file, I can run it and generate the residuals plot
But when I try the simplest flow problem starting a new Fluent module from Workbench, I can't generate the residuals plot and Fluent appears to not respond for a while. Below are screenshots of my setup sidebar for my old case file and the new one (that doesn't work). Everything is the same except under the Used Licenses bar. Is this a problem?
*working
*not working
When I use my old .cas file and delete the current geometry to redraw the simple test geometry, the solver works and I can see the residual plot as well as the correct solution.

[rigustafson]

I am still having this issue, and it seems like even using the old .cas file doesn't always work. Any new ideas?

[rigustafson]

I saw this error: