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Test Equipment

Home Forums Archive Distributed Research Projects Test Equipment

This topic contains 19 replies, has 6 voices, and was last updated by Profile photo of Wayne-Gramlich Wayne-Gramlich 6 years, 5 months ago.

Viewing 5 posts - 16 through 20 (of 20 total)
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  • #3274
    Profile photo of vincecate
    vincecate
    Participant

    In this same forum I posted about using “blender” for simulations, with some links to fun videos:

    http://seasteading.org/interact/forums/research/distributed-research-projects/working-with-blender-simulate-fluid-dynamics-

    #3328
    Profile photo of Wayne-Gramlich
    Wayne-Gramlich
    Participant

    Our understanding is that the ocean engineering field uses computational fluid dynamics (CFD) to do the initial analysis of designs. The CFD codes are good, but they are unable to handle some of the more subtle issues related to fluid dynamics, so the ultimate test is to build a scale model and stuff it into a wave tank. Apparently, the scaling limitations are well understood and “workable”. A good wave tank is expensive to build and run, so it can cost upwards of $10K/day ($US) to rent a professional wave tank. Hence, the use of CFD models first.

    #3329
    Profile photo of Wayne-Gramlich
    Wayne-Gramlich
    Participant

    Both 3 axis tilt sensors and 3 axis rate gyros are readily available from places like SparkFun . Melding the resulting data into something useful is actually a little tricky. Kalman filters are typically used. Rate gyros suffer from drift. Tilt sensors suffer from noise. Designing a Kalman filter to integrate the two sensors is not particularly easy.

    An alternative that is used is to mount 3-LED’s on the platform and video tape it with a couple of cameras. There is software that can track the LED’s and figure out the angles and accelerations.

    #3331
    Profile photo of thebastidge
    thebastidge
    Participant

    Holy Crap.

    Better have your test protocols worked out precisely in advance at those prices, and some empirical testing in a cheaper (uncontrolled) environment (like a lake) would be a good idea too, just for simple “gotchas” even if the measurements are of only limited usefulness. This would give you a chance to practice setting up and tearing down your test model so you don’t waste the time that you’re paying big bucks for.

    #3348
    Profile photo of Wayne-Gramlich
    Wayne-Gramlich
    Participant

    At $10K/day, you have to wait your turn to get a shot at the tank. 6 to 9 month back logs are quite common.

Viewing 5 posts - 16 through 20 (of 20 total)

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