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working with "blender" to simulate "fluid dynamics" making a "numerical wave tank"

Home Forums Archive Distributed Research Projects working with "blender" to simulate "fluid dynamics" making a "numerical wave tank"

This topic contains 6 replies, has 6 voices, and was last updated by Avatar of Borodog Borodog 5 years, 5 months ago.

Viewing 7 posts - 1 through 7 (of 7 total)
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  • #577
    Avatar of vincecate
    vincecate
    Participant

    On Linux there is some free software called “blender” that can do really nice 3D simulations, including fluid dynamics. I don’t know of any other free software that is closer to a numerical wave tank for visualizing results. Does anyone? For examples see:

    http://youtube.com/watch?v=SMxfzil5_qU

    http://youtube.com/watch?v=azuNHuj0cjo

    (first I was not sure this was a simulation, but there are no bubbles)

    http://youtube.com/watch?v=Rv-ExKhhhZg

    (not just limited to normal laws of fluid dynamics)

    http://www.youtube.com/watch?v=ocnLSuuljPo

    http://www.youtube.com/watch?v=NJ0Alb5bgE8

    http://youtube.com/watch?v=I3O62oyTKDY

    http://youtube.com/watch?v=9yEdiIw2VWY

    http://youtube.com/watch?v=UJPn3jhbt7s

    http://www.youtube.com/watch?v=aRhKs9clRS4

    http://www.youtube.com/watch?v=gtvmHutR0bc

    http://www.youtube.com/watch?v=I-80sFggoig

    http://www.youtube.com/watch?v=-AiLyQWXjIg

    http://www.youtube.com/watch?v=bKHKVNoECO8

    Not sure the above is fluid dynamics. You can just define wave motion in blender without simulating the physics of water. But the ocean looks cool and it has a boat on it so I am including it anyway.

    http://www.youtube.com/watch?v=AbYbv3tSA1s

    This last video has a boat in a wave tank. I think he had the top of the area the water could go to so low it was hitting the top. Also, this was 2 years ago and blender has been improving. This video shows the idea of testing something in a simulated wave tank. I think it is possible to do much better than this now.

    http://www.youtube.com/watch?v=fqKVjKo96Es

    Here is a simulation of boat with a prop pushing in a wave tank. This in the kind of thing, but with waves.

    http://www.youtube.com/watch?v=g2lsuk4rybY

    This is of a lighthous on a tiny island with a big wave hitting it. This is very close to the kind of simulations I would like to see for seasteads. But deep ocean waves not shallow water waves.

    At the moment it is not easy to setup a “numerical wave tank” and test some ocean structure. But it can be done. If someone setup a simulation we could all use it. And judging from the cool 3D pictures people have made, I am sure we have people here who can do this.

    Also, blender is open source. We have programmers in this group. It would be possible to make it “wave tank test friendly” where users could enter a few parameters and do some tests. Would make it much easier/cheaper/faster than building models and paying for a real wave tank. So things could move along faster.

    Ideally you could draw something in Google SketchUp and then drop it into a blender simulation to test how it works and make a cool video. Then post the video on youtube so everyone can see the results. For rigid structures I think this should be possible. Would need to be able to specify the density of the different parts. If you have lead ballast and aluminum structure you have to let blender know both of these. I am not yet worried about testing the strength of the structure, just the stability when interacting with waves.

    Seems you can import SketchUp objects into blender:

    http://www.blendernation.com/2006/05/11/import-sketchup-and-google-earth-files-into-blender/

    http://blender-archi.tuxfamily.org/Import_your_model_from_your_Architecture_drawing_software

    Seems like a good project for people here to work on. It is a way to use the computer skills we have in this group to attack the ocean engineering problem. The resulting system would be good for seastead research and for other people too. Do people like this idea? Or do we just want to use real wave tanks? Are there people here with the time, skills, and inclination to make blender work for us?

    If nobody here wants to do it, maybe the Seasteading Institute could fund one of the blender developers to make an easy to use numerical wavetank so we can just draw something in SketchUp and then simulate it in blender under different wave types? For someone familiar with blender what we need is probably not that hard to create. So it probably would not cost too much.

    #3286
    Avatar of Carl-Pålsson
    Carl-Pålsson
    Participant
    #3327
    Avatar of Wayne-Gramlich
    Wayne-Gramlich
    Participant

    Our understanding is that there is standard CFD (Computational Fluid Dynamics) software used by the ocean engineering industry. I don’t think they use blender tho’.

    #3330
    Avatar of vincecate
    vincecate
    Participant

    If the standard CFD software costs $10,000/user we might still be very interested in using the free “blender” software. What do they use and how much does it cost? Also, blender was not so powerful just a short time ago. So it may just be tradition that they use what they use, not that it is better. Also, even if the standard software is in some ways better, there might be important features that make blender better for us. For example, blender can import a Google SketchUp drawing, if the other software can’t I might choose blender just because of that.

    #3598
    Avatar of scrag_10
    scrag_10
    Participant

    I am a blender user!

    http://wiki.blender.org/index.php/Manual/PartX/Fluid_Simulation
    
    It says what kind of formula it uses somewhere there (been a while since I read it), but I imagine it doesn't the standards, and if it doesn't it is open source you can hire someone to make it better and then share the source code with the blender community, which is cheaper then paying for a Properitary App.
    
    **Also the first one you think that might not be a simulation isn't.
    
    
    
    So you know how powerful blender is check out the short movies, Big Buck Bunny, and Elephants Dream. Should beable to find 1080p copies out there, free to download.
    
    sincerly me. ps I might be able to help with blender stuff, feel free to email me.
    scrag_10@hotmail.com
    

    #5161
    Avatar of bkemper
    bkemper
    Participant

    My firm uses CFD. If I see a reaonable application for it, we’ll pitch in. I’m still learning this project. However, boyancy is another issue, as is sloshing. There are other codes out there that allow for very complex water action modeling…and they are more expensive.

    Realistically, at some point these will be needed to do proper due dilligence to have reasonably design for safety and reliability.

    Bart Kemper, P.E.

    #5301
    Avatar of Borodog
    Borodog
    Participant

    I posted in the Engineering section, but I’ll repost this here. I’m a professional CFD engineer and am willing to do some work in my spare time.

    While blender makes beautiful movies, the fluid engine is not a realistic engine. It is designed to produce motions that look like real fluids to the human eye without all the pesky overhead of actually calculating a realistic solution.

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