When using parallel Fluent on Linux or Windows with shared memory on a local machine, the Intel 2021 MPI may show the following disadvantages compared to Intel 2018:
memory consumption increases, especially as the number of processes increases
To avoid this issue, the use of Intel 2018 as a fallback is supported as a legacy feature.
You can request the use of Intel 2018 when launching Fluent, by using either the
-mpi=intel2018 command line option or the
USE_INTEL_MPI_2018=1 environment variable.