Well, you guys seem, well a little down on Autodesk freeware, just so you can go on-and-on-and-on about what stuff can't do, remember it's freeware - I'm going to write a new thread on freeware recommending 3Dish, CADish freeware over the next little while, so you can just whale away at it. Expect it over next few days.
For Now
Autodesk Falcon doesn't satisfy? Then you haven't heard of Autodesk's Education Program. Would a free student copy of Autodesk Simulation CFD 2013 satisfy? They even will let you download if your in between jobs and unemployed and help you learn a new skill with their free online training University. Can you ask for anything more ?
Autodesk Simulation CFD 2013 Free Education Download Center - and about 30 of their other applications:
http://students.autodesk.com/?nd=home&logout=1