Hi all,
i’m quite a newbie of blender and this is my first post here. I’m trying to simulate something that is very similar to a water mill : an Archimede’s screw. In the video linked below an example of what i would like to simulate with blender. Is it possible to make somehow the fluid and a hinge interact? i’ve already tried something in the last days but without any success 
any advice is very appreciated
Thanks in advance !
Andrea
It is possible to fake the effect using a fluid sim. I doubt you’ll have much luck trying to simulate the water pushing the screw and turning it into rotational energy. Instead I would probably just keyframe the screw turning and make that an obstacle for the fluid sim. The water will bounce off the screw and give the illusion that it is causing the screw to turn.
Thanks for your answer, so you are suggesting me not to take blender as “scientific” simulator? because i would like to simulate how much torque can the water generate on the screw. For what i learned blender is top for rendering, i was wondering if it has also some scientific approach.
Thanks for your answer, so you are suggesting me not to take blender as “scientific” simulator? because i would like to simulate how much torque can the water generate on the screw. For what i learned blender is top for rendering, i was wondering if it has also some scientific approach.
I doubt it could be done in a true sense of following any legimate fluid dynamics equations. The physics engine blender uses (called “bullet”) is geared more toward fake it and do it faster, designed for vfx and not really for scientific modeling. My philosophy with Blender is “there is always a way” Although in this case I don’t know if there is. I hope I’m wrong.
There is a fluid simulator software (not associated with Blender) named Houdini which could probably handle it. I believe you may be able to output your simulations and render them using blender.
This is a somewhat realistic version of the screw I made using Blenders fluid system. The rotation is all fake, but the interaction of the water and the screw is real. If you want the blend I can post it. It took about 15 minutes to bake on an i5.
Wow ! it’s very cool to see what you have rendered ! i’m trying to have a look at Houdini, as it is not open-source it can be a problem. I’ll try the “apprentice” version since i want to simulate for research purposes not commercial. I really would like to see your blend file for this simulation to see how you set up the case.
Really thanks !
Here is the blend file on dropbox for that simulation.
I think you’ll need to bake it on your machine. I have the resolution at 200, for quick tests you would normally lower that way down to maybe 50-80 depending on your machine, and when you want a high quality one crank it to 200+ and let it cook for awhile. Any questions feel free to ask.
I have a couple ideas on how to fudge the sim in blender, get some force vectors from the fluid and fudge that into torque, but even in my head it’s insanely ugly. I would continue investigating a dedicated simulation package like houdini.
Here’s a 6 minute video explaining how this sim is set up and how to alter it and re-bake.
nice answer Photox would agree you have to cheat in blender 
didn’t know Houdini did fluid sims (long time since I looked at that soft lol )
to OP I don’t know if this will do the job [ http://www.openfoam.com/ ] only found it the other week and NOT tried it !!
Open foam looks really cool, I’ll have to check it out. Regardless of the software it will be a little tricky to set up as you have cyclic dependencies. The water exerts a force on the screw, which turns the screw, which then affects the flow of water, which then affects the screw…
It’s certainly doable, but my gut feeling is that it will require a lot of coffee.