Create a laminar flow jet without pesky fiber optics.

[ApexLogic] had some PMMA core acrylic rod rod left over from a project and decided to use it as the lighting element in a laminar flow water jet.

The typical water jet consists of a bunch of sponges and drinking straws sandwiched together to slow a rough water stream and then a finely cut nozzle to provide a smooth ripple-free strand of clear water. If light is applied to this stream of water it tends to act similarly to fiber optics. [ApexLogic], however, uses a combination of shaved PVC filings, Brillo, and what appears to be most of the plumbing aisle of a local hardware store to get the same laminar flow. To top it off the polished acrylic rod is much less fragile than its glass-fiber counterpart and can have a high power light glued to the end for a nice water tight seal.

The system currently runs off of garden hose pressure, and would probably need some kind of a boost before it went into that front yard mega fountain that [Caleb] is still waiting for somebody to make.  If you still need some clarity on laminar water jets check out these videos on a few

Comments

  1. Eirinn says:

    Gotta love laminar water jets. They look spectacular when used in fountain systems.

    • Eirinn says:

      …actually does the title to this article make sense? Isn’t laminar flow jet entirely water based and has nothing to do with fiber optics?

      nb: there’s a typo: “wthout”

      • sneakypoo says:

        Yeah I found the title a bit odd as well.

        Been meaning to make one of these for shits and giggles but I’ve never gotten around to it. Not having a backyard to soak might have something to do with it though…

      • Sheldon says:

        While the actual laminar flow never uses fibre-optics, however I think the title refers to the creators use of a solid piece of acrylic (in the linked guide, it says “Most lighted laminar jets use fiber optic filaments to carry light through the jet and emit it into the stream of exiting water” which I would guess is the origin)

      • Bob D says:

        Well, the nonsense title did trip my curiosity enough to click through the RSS feed to see what the hell they were talking about. Maybe it’s a new tactic to drive traffic?

  2. angus says:

    > plumbing isle

    Should be “plumbing aisle”. Do you guys have a policy of putting a spelling/grammar error in every second article?

    The water jet does look awesome.

    • wb says:

      It’s the Isle of Plumbing–A plumber’s dream.

    • charles says:

      Well I guess that would depend on the layout of your local hardware store wouldn’t it? Mine has a predominantly displayed sign stating “Paint Isle” seeing that it is a circular desk with an attendant in the middle.

      What is being ignored is this:

      “…what appears to be most of the plumbing aisle of a local hardware store…”(hey it’s fixed)

      Being the funniest and most relatable article joke in recent memory.

  3. Drake says:

    Couldnt you achive the same effect by using edge lighting?

    For instance at the end before the nozzl eyou can have a 1/8 in thick piece of acrylic the same size as the whole assembly. Have the nozzle hole lazer cut into the acrylic. Then use your led(s) around the outer edge.

    • ApexLogic says:

      You won’t have nearly the same effect Drake. For example, if you took a piece of fiber optic filaments and attempted to light it from the side, rather than the end it will only transfer a fraction of the light that is emitted onto it.

      The water in the form of a laminar stream works the same way. Carrying the light through the stream, only emitting it from the sides where imperfections exist within the stream.

      On a side note, having the stream land onto a mirror at the correct angle will simulate a “double pump” effect. Transferring wasted light back into the stream causing it to be much brighter.

      • They live by a code, and it's usually SMPTE says:

        I suspect this would be short lived, as water is quite abrasive. However, do you have empirical evidence of this effect or is this a theoretical construct?

        I ask because I’ve experimented with strobes to attempt to show synchronized droplets and would find it interesting to “back light” them with slowly changing phase delays to give the effect of a single droplet or water segment moving back and forth ala pong.

  4. They live by a code, and it's usually SMPTE says:

    I built a ghetto laminar flow unit from little coffee straws packed into a 3″ galvanized pipe, preceded by a 4″ length of galv pipe stuffed with small diameter straws (restaurant unnamed) and preceded by a six inch length with regular straws packed in. Total cost $6, had I paid for anything.

    It worked remarkably well, and I’m not sure every stage was needed – it stayed laminar for about 16-18″ before it was gradually broken up by turbulence.

    These are quite water-pressure dependent, and the whole system can have resonant effects if you use a recirculating pump .

    • ApexLogic says:

      “These are quite water-pressure dependent, and the whole system can have resonant effects if you use a recirculating pump .”

      You are absolutely correct. By design a recirculating pump will make the stream of water appear to “jitter”. This is caused by a pulsing flow that the pump creates. To remedy this situation a bypass tank is used.

      The bypass tank is a sealed tank that has an inlet and an offset outlet. At the top of the tank an air bubble forms and compresses. This smooths out both the jitter problem and the variable pressure that occurs with a recirculating pump. I will have a write up on building one of your own in the near future.

      • They live by a code, and it's usually SMPTE says:

        Indeed.

        There are other methods; many fountains suffer from these effects (which can be pleasing…) – but it’s easy to resolve.

        In essence, any closed fountain is a filter network. You can think of capacity as capacitance (what with that being the source for the word capacitor and all), while the diameters of the pipes/paths are (of course) resistance.

        The pulsations can be altered just exactly as one would correct for RC filter curves – all you have to do is alter the path by changing the R or C equivalent. To some extent, the use of flexible tubing corresponds to inductance, but I would caution against it.

        I’ve fixed fountains by simply altering the path of obstacles (baffles) in the flow, in essence tuning the circuit, or by adding or removing rocks to change the constants. It’s not the pulsation from the pump that swamps the “circuit”, but the harmonics of the system.

        Your baffle is the addition of an RC network at the source. Someone mentioned sponges, but I really think sponges are a bad idea for long term installations; any laminar device is essentially a combination filter and water knife.

        My favorite laminar water exhibition was a laminar dome/spiral that would collapse at random; kids loved it. I’d rather have the graphical drip fountain than the sheet waterfall, but it might make an interesting shower.

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