The SU2 adapter now leverages the SU2 Python wrapper and preCICE Python bindings to couple SU2 using preCICE in a minimally invasive way. This adapter simply updates existing functions and implements new ones in the SU2 Python wrapper that allow for simple preCICE implementation with implicit coupling. In addition, Python scripts are provided that can be used to quickly run FSI or CHT, or can serve as templates for your own custom application. This adapter currently works for SU2 versions 7.5.0 and 7.5.1 "Blackbird". Both conjugate heat-transfer and fluid-structure interaction can be completed with this adapter.
This adapter has been designed to work when using the compressible solver for unsteady problems with dual-time stepping, for single-zone problems. Implicit coupling currently saves the flow solution, turbulence solution, and the mesh solution (for mesh deformation). Species transport and transition model variables at this time are not saved, but may be straightforward to implement.
Download SU2 v7.5.1 "Blackbird" from directly from https://github.com/su2code/SU2/releases/tag/v7.5.1. Note that both swig and mpi4py must be installed to use the SU2 Python wrapper. After installing the adapter, the flag -Denable-pywrapper=true must be specified.
In addition to having successfully installed preCICE, the preCICE Python bindings must also be installed. For installing preCICE, please navigate to https://precice.org/installation-overview.html. After successfully installing preCICE, please follow the instructions at https://precice.org/installation-bindings-python.html to get the preCICE Python bindings. As a test, run the following command:
python3 -c "import precice"
If there are no errors, then preCICE and its Python bindings were successfully installed.
In order to couple SU2 using preCICE, python_wrapper_structure.cpp and CDriver.hpp must be updated. This adapter provides the updated files. The shell script su2AdapterInstall, which comes with this adapter, automatically replaces the files in your SU2 directory with these updated files and provides the correct commands to re-configure and re-install SU2 with the added adjustments. For this to work, the SU2_HOME variable must be set to your SU2 directory prior to running.
SU2 will advise you to add this variable (and others) to your ~/.bashrc (Linux) or ~/.bash_profile (Mac) after configuring, so it may already be set if SU2 is already configured and installed on your computer. To install the adapter, run from the adapter directory:
./su2AdapterInstall
The script will not execute if the environment variable SU2_HOME is not set or empty.
If you do not want to use this script, manually copy the files to the locations given in it. The environment variable needs to be defined as stated above, nevertheless.
After copying the adapter files to the correct locations within the SU2 package, SU2 can be configured and built just like the original version of the solver suite. Please refer to the installation instructions provided with the SU2 source code. SU2 should be built with MPI support in order to make use of parallel functionalities and must be built with pywrapper functionality enabled. The script su2AdapterInstall states recommended command sequences for both the configuration and the building process upon completion of the execution.
To utilize the default FSI and CHT scripts anywhere, add to your ~/.bashrc:
export PATH=/path/to/adapter/run:$PATH
After successfully installing the adapted SU2, the default FSI/CHT scripts may be utilized. Note that these scripts currently are designed for a single coupling mesh, called interface. However it is extremely easy to update these scripts to handle a different BC name and/or multiple interfaces. They are provided simply for their ease of use.
To set up a single-interface FSI problem for coupling with preCICE, the SU2 config file should have the following:
DEFORM_MESH= YES
MARKER_DEFORM_MESH= ( interface )
The interface marker should also be set as a wall boundary, such as MARKER_EULER or MARKER_ISOTHERMAL.
By default in the SU2_preCICE_FSI.py script, the following settings are automatically used for coupling with preCICE:
- preCICE Participant Name: Fluid
- preCICE Config File: ../precice-config.xml
- preCICE Mesh Name: Fluid-Mesh
- preCICE Read Data: Displacements
- preCICE Write Data: Forces
and a fluid domain dimension of 3 is presumed.
To run with these settings:
SU2_preCICE_FSI.py -f SU2_config_file.cfg --parallel
The --parallel flag must always be used when SU2 is built in parallel, even if running on a single process. If you do not build SU2 with MPI, do not include it.
The read/write data are hardcoded, but the participant name, config file, and mesh name can be changed using flags in the call to the Python file. In general, to run an FSI case:
SU2_preCICE_FSI.py -f SU2_config_file.cfg -p participant_name -c precice_config_file -m precice_mesh_name -d 2 --parallel
To set up a single-interface CHT problem for coupling with preCICE, the SU2 config file should have the following:
% For having SU2 read temperature, write heat flux:
MARKER_ISOTHERMAL= (interface, ______)
%
% For having SU2 read heat flux, write temperature (the -r flag):
MARKER_HEATFLUX= (interface, ______)
%
% And in both cases include:
MARKER_PYTHON_CUSTOM= (interface)
Note that the blank spots in the isothermal and heat flux markers are the initial BC values. If there is a data initialization from another solver, they will be updated and are not important.
By default in the SU2_preCICE_CHT.py script, the following settings are automatically used for coupling with preCICE:
- preCICE Participant Name: Fluid
- preCICE Config File: ../precice-config.xml
- preCICE Mesh Name: Fluid-Mesh
- preCICE Read Data: Temperature
- preCICE Write Data: Heat-Flux
and a fluid domain dimension of 3 is presumed.
To run with these settings:
SU2_preCICE_CHT.py -f SU2_config_file.cfg --parallel
The --parallel flag must always be used when SU2 is built in parallel, even if running on a single process. If you do not build SU2 with MPI, do not include it.
The read/write data for CHT can be reversed if the preCICE config file specifies for the fluid to read heat flux and write temperature. This can easily be accomplished with the -r flag:
SU2_preCICE_CHT.py -f SU2_config_file.cfg -r --parallel
The participant name, config file, and mesh name can be changed using flags in the call to the Python file. In general, to run a CHT case:
SU2_preCICE_CHT.py -f SU2_config_file.cfg -p participant_name -c precice_config_file -m precice_mesh_name -d 2 --parallel
The Python scripts can very easily be run in parallel by just pre-pending the Python script call like:
mpirun -n 8 python3 SU2_preCICE_CHT.py -f SU2_config_file.cfg --parallel
NOTE: As of SU2 v7.5.1: Deforming MARKER_EULER's are buggy when simulations are run in parallel, leading to unexpected results. More information can be found at this discussion here: su2code/SU2#1931.