I am using openfoam to calculate the flow field of a rectangular section channel with a cage in it and try to analysis the influence of the blockage on particles transport. I plan to inject particles in the cage, which means only part of flow field is what I exactly need, thus I used decomposePar to divide the cage into processor1 in order to reduce calculation time and after steady state I created a new case inwhich 0/,constant/ were from processor1, I got correct U,p... and polymesh, which all perfomed well in paraview. I redefined the boundaries by creatPatch. But when running the new case with particleFoam I always got an error "Not implemented...FOAM aborting". I think maybe BC causes this error but don't know how to fix it. So how to fix this error or maybe there is more appropriate methods to achieve this? My English is not very well, thank you for reading this and all your help！
To extract a specific part of the flow field in OpenFOAM and start a new project on it, you can follow these general steps:
1. Identify the region of interest: Determine the specific part of the flow field that you want to extract for your new project. This could be a particular geometry, a region within the domain, or a specific time frame of the simulation.
2. Define the extraction criteria: Specify the criteria for extracting the desired part of the flow field. This can include conditions based on geometric boundaries, cell labels, time steps, or any other relevant parameters.
3. Use the appropriate OpenFOAM tools: OpenFOAM provides several utilities and functions that can help with extracting and manipulating the flow field. Some commonly used tools include:
- `patchAverage`: This utility can be used to extract averaged values on a specified patch or surface.
- `foamToVTK`: This utility converts OpenFOAM data to VTK format, which is widely supported by visualization tools.
- `sample`: The `sample` utility allows you to sample the flow field at specific locations and save the data in a new file.
- `fieldMinMax`: This utility can be used to find the minimum and maximum values of a field within a specific region.
4. Write custom code or scripts (if needed): Depending on your specific requirements, you may need to write custom code or scripts to perform more complex extraction tasks. OpenFOAM provides a comprehensive C++ library for customization and development.
5. Start a new project: Once you have extracted the desired part of the flow field, you can start a new project based on it. This may involve setting up a new case directory, adjusting boundary conditions, mesh refinement, or any other necessary modifications for your new simulation.
6. Perform analysis or simulation: With the extracted flow field and the new project setup, you can now perform your desired analysis, post-processing, or simulation on the specific region of interest.
Remember to carefully document your steps and maintain clear organization to ensure reproducibility and traceability of your work.
Gopal Sharma Thank you for your very detailed reply! I will remember your suggestions in my future work.
As I mentioned before, the steady state flow field in the cage is what I wish to extract, considering that it is a regular geometry, I use manual decomposion to put it into processor1 following the method mentioned in [1].
And It worked well, openfoam created a new polymesh/ in processor1/constant/ which only included the domain I wanted, I took latest time result as initial condition, and assembled them into a new case in openfoam. But no data of boundraies existed in it. For openfoam set BC of internal faces as 'processor' in order to interact with other processors when decomposing, so I need to redefined the BC that could connect internalField with boundraies. I think it is the internal faces of type 'processor' cause this error.
For the 'sample' you mentioned, I don't whether it could sample data in a whole specific domain as well as it's boundraies. Besides, how to initialize the BC of internal faces after sampling?
These days I have chosen a compromise to reduce calculating time. I built a new model with the same geometric dimensions and created same cells in the cage domain while much fewer cells everywhere else. Then used 'mapFields -consistent' to initialize entire flow field, which greatly shorten the calculation time. But Im still interested with this problem and really thank you for your information.
[1]https://www.cfd-online.com/Forums/openfoam-pre-processing/193573-manual-decomposition-using-setfields.html
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