Aerofoil underwater

Discussion in 'Hydrodynamics and Aerodynamics' started by endorium, Oct 19, 2012.

  1. DCockey
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    DCockey Senior Member

    Another possibility would be a flexible hose with the output end free to move around. Get the right combination of length, stiffness and mass and the hose should oscillate.
     
  2. messabout
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    messabout Senior Member

    DCockey has the right idea. This is similar to a pool toy that can sometimes be found in pool supply stores.

    If your main purpose is to aerate the water then just arrange the outlet above the water surface and arrange for it to have multiple small streams like a shower head. Also a simple waterfall will aerate, particularly if the fall distance is fairly large so that splash and turbulence occurs. Sewage disposal plants sometimes use this method for oxygenating the slurry so that the microbes are encouraged to do their thing.
     
  3. Billwrin
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    Billwrin New Member

    I've spent some time working with fish keeping and these are very good solutions. No matter how much turbulence you have under water very little oxygen is exchanged. You HAVE to do it at or above the surface. A simple single stream into the air then back into the tank will work infinitely better than anything you do under water.

    Another simple solution for aerating water is to aim a fan at the surface.

    To address your original post. Yes, you can manipulate the exit of a pipe to cause turbulence.
     
  4. endorium
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    endorium Junior Member

    Aeration is not what I am tryign to achieve. I am trying to achieve a pulsing affect to creat a random water movement within the aquarium. In a way simulating wave motion
     
  5. DCockey
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    DCockey Senior Member

    In that case try the oscillating hose or possibly several oscillating hoses of different lengths and therefore different frequencies.
     
  6. Billwrin
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    Billwrin New Member

    Oh, I misunderstood or maybe read too much into a previous reply. You need a dump tank.

    I once made a device for simulating wave action without any moving parts but it sounded like a toilet flushing every cycle. You'd be much happier with a dump tank(one moving part).
     
  7. endorium
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    endorium Junior Member

    Dump tank? I am not sure how I could use this idea. Can you elaborate?

    Thanks again people for all your help
     
  8. Billwrin
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    Billwrin New Member

    It took a minute to find it. Dr Walter Adey invented a system in the late '70s. The dump tank was an important part of a bigger system. It's no longer available for consumers, you'll have to make your own.

    If you Google U.S. Patent 4333263 and look at item number 20 in figure 3 you'll see a crude drawing of what he called a wave generator at the time. It later was known as a dump tank.

    When it's empty it rights its self then as it fills with water the center of gravity moves past the pivot point then "dumps". As long as you pump water into the dump tank and it doesn't get obstructed it'll continue to make waves in a very predictable way.
     

  9. philSweet
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    philSweet Senior Member

    Dumptanks work fine. One moving part if you can live with that. If you are careful and clever, there need be very little actual change to the submerged surface of the the devise, if you are worried about dammaging fragile stuff. I've toyed around with quite a few small fountains and water features and a pulsing flow helps add interest when space and flow is small.
     
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