Project Falcon is a free technology preview that simulates airflow around object “Project falcon”.
If you try to install the version for Inventor 2013, you will notice that the add-on is not made available and if you previously already downloaded the 2013 add-on version you will encounter a “Falcon For Inventor expired” error message.
This is due to the fact that the 2013 version has a “time bomb” in it, which has now run out.
In this case, you should download the “Microsoft Windows Standalone Application” stand-alone version. It runs all by itself and does not require Autodesk software.
To use it in conjunction with your Autodesk Inventor files, you will have to export a STL file from inventor and then load the STL file in to the stand-alone “Microsoft Windows Standalone Application” program.
Thank you to Scott Sheppard for helping clarifying the situation.