[raushan kumar]

Hello friends,

I have found an issue in my adaptive mesh refined grid, specifically when I restart my case from a non-zero time. I am using VOF solver for multiphase simulation. When I am running my simulation continuously the mesh adaptation is uniform but after restarting the simulation at a non-zero time, then the mesh adaptation is not uniform as shown in the attachment.


The refinement is done based on a volume fraction gradient basis as shown in the attachment (adaptive mesh setting). I have used adaptive mesh refinement criteria on a gradient_0 basis. But, As I restart my case, the mesh does not refine uniformly. Please find the attachment to see the issue clearly.

Please,Please, just take a look at the images in the attachment to see what I am exactly talking about? The images show the various images of non-adaptive mesh. I am looking for a solution.

[raushan kumar]

Originally Posted by raushan kumar

Hello friends,

I have found an issue in my adaptive mesh refined grid, specifically when I restart my case from a non-zero time. I am using VOF solver for multiphase simulation. When I am running my simulation continuously the mesh adaptation is uniform but after restarting the simulation at a non-zero time, then the mesh adaptation is not uniform as shown in the attachment.


The refinement is done based on a volume fraction gradient basis as shown in the attachment (adaptive mesh setting). I have used adaptive mesh refinement criteria on a gradient_0 basis. But, As I restart my case, the mesh does not refine uniformly. Please find the attachment to see the issue clearly.

Please,Please, just take a look at the images in the attachment to see what I am exactly talking about? The images show the various images of non-adaptive mesh. I am looking for a solution.

Here I am writing about my experience with Fluent in steps and how the problem has been resolved given in step 3.
Step 1- I launched the fluent through the workbench2020R1. I saved the case and data files in the Legacy format. Then I launched a new workbench2020R1 and imported the case and data files in the .cas.gz and .dat.gz formats and rerun the simulation and again saved the files in the Legacy format. In this case, mesh adaptation is non-uniform while restarting the simulation at the non-zero time step.
Step 2- I launched the fluent through the workbench2020R1. I saved the case and data files in the Legacy format. Then I launched Fluent standalone 2023R1 and imported the case and data files in the .cas.gz and .dat.gz formats and rerun the simulation and here saved the files in the CFF format (.cas.h5 and .dat.h5). Then again I launched a new Fluent standalone 2023R1 and imported the .cas.h5 and .dat.h5 files at non-zero time step and run the simulation. Then again I am getting a non-uniform mesh adaptation.
Step 3- I launched the fluent through the workbench2020R1. I saved the case and data files generated at 0 th time step in the Legacy format as there is no option of saving it into CFF format under Fluent 2020R1 launched through Workbench. Then I launched Fluent standalone 2023R1 and imported the case and data files in the .cas.gz and .dat.gz formats and saved the case and data file in the CFF format (.cas.h5 and .dat.h5) for the 0th time step. Then again I launched a new Fluent standalone 2023R1 and imported the .cas.h5 and .dat.h5 files at the zeroth time step and run the simulation saved files in CFF format. Then I stopped the simulation and restarted it after importing the case and data files in .dat.h5 format at a non-zero time step in the Fluent standalone 2023R1. Now, I am getting the correct mesh adaptation after restarting the simulation.