Can I couple two participants one-way?
Yes! Several people are doing this already.
Even though there may be other ways to do one-way coupling, it may still be beneficial to use preCICE here: flexible data mapping methods, parallel communication (your coupling data might be too large to write to disk), and already adapted solvers.
Moved from our FAQ on precice.org.
A detailed discussion on a specific example with OpenFOAM and CalculiX was moved to a new topic: How to configure one-way coupling