Plastic Beach - Water Wave Machine

[hydrophyte]

Here it is set up again with the new lighting and aquascape too...



I'm going to add a couple of plants as emergents on the far left side. There is a 3.5" net pot filled with stones there in the spot I saved for them. I think I might combine a mat of vining Hydrocotyle with a mini Calathea or other more erect plant. ..



I probably won't leave it up long, but here's a quick video from my Instagram showing operation...

 

[Chrispowell]

Great project! Would love to replicate a mangrove brackish tank like this!

 

[hydrophyte]

Great project! Would love to replicate a mangrove brackish tank like this!

Thanks!

Yep, a mangrove tree planting would serve dual purpose of creating an authentic kind of biotope environment while also dispersing the wave energy at the far end of the tank. I plan to next do a setup like this, but in a 48" long tank. Which could be a nice platform for mangroves with some brackish water killis and poeceliids.

 

[hydrophyte]

Here's another concept I wonder about for adapting as a planted aquascape....



Instead of a long linear aquarium like I am using with the wave machine, I would build a ripple setup with a broad and shallow square tank. This is a 24" X 24" X 8" enclosure currently housing another project....



I really like this tank shape. The view in through the top of the water is such a pleasant, natural perspective.

As with the wave machine, a ripple tank mechanism could serve as an energy source supplementing the water filtration for water movement and model ecosystem health. Ripples in the water surface would provide an additional kind of kinetic sculpture interest, while they would also reflect onto the ceiling and wall surfaces with the aquarium light source.

 

[Ed Wiser]

 

[hydrophyte]

I've been thinking about the ripple tank idea some more as a continuation of this project. Ripple tanks are often used in physics classrooms, so it's pretty easy to find details and a number of kits online as well. The basic setup is most often a shallow enclosure filled with just a few cm of water and with a paddle that vibrates or actuates to create the water ripples.



(Attribution: Ripple tank - Wikipedia , via Wikimedia Commons)

The most essential difference between this device and a wave tank is that the waves are of very short amplitude. The ripple tank may also have a clear enclosure bottom for projecting the ripple patterns with a bright light source. Most ripple tanks are square in shape, while wave tanks are more linear to allow for longer wave travel.

Ripple tank paddle motion is usually achieved with a small attached DC motor spinning an asymmetrical "eccentric" mass which causes the assembly to take a short hop with each revolution. Other designs may use an electromagnetic vibrator driven by a sine wave signal generators. While this kind of setup is more costly than the simple electric motor-driven paddle, you could say it has more conceptual appeal. The electromagnetic vibrators are also kind of interesting devices and could thus serve as a visible hardware element as part of the whole display.


Here's a really interesting video showing a ripple tank with this kind of wave generation.



The spring steel ring transferring the energy to the paddle in this configuration could be an additional sculptural feature of interest. Notice also that the mechanism can cause quite significant water movement, another compelling feature of both wave tanks and ripple tanks adapted as aquarium display; this is a way to energize the system with modes of water movement more natural than air bubbling or electric pump impellers.

 

[Dogtemple]

I’m loving your take on this, really refreshing to see something new (and mechanical).

With the ripples, are you looking to make small ripples? First thing that came to my mind would be to have a drop of water land in the centre of the tank to create a ripple. Largely for simplicity of building

 

[hydrophyte]

I’m loving your take on this, really refreshing to see something new (and mechanical).

With the ripples, are you looking to make small ripples? First thing that came to my mind would be to have a drop of water land in the centre of the tank to create a ripple. Largely for simplicity of building

Thanks for following along!

Water drops could make more natural, peaceful ripples, but I'm exploring the mechanical actuator idea because it willvmove more water, because it will allow for more precise exploration of some of the physics and because the mechanism will serve like a kinetic sculptural element with the whole setup.

Once I round up some of the materials, I'll start a new discussion for this idea.

 

[hydrophyte]

I got this scaped with a few plants. This is just a Spathiphylum, a Calathea and some Bacopa monnieri I had on-hand and put together riparium-style in a 4" net pot. Bacopa stems will grow some more to cover the pot while also dampening the wave energy.



There are some pretty cool ways that this could be combined with living aquaecapes. Here's a few more ideas:

1. Wabi Kusa, with a few lave stones in front and around the sides to disperse wave energy.
2. Syringodium, Ruppia or other Seagrasses to represent a sandy flat with a saltwater setup.
3. Aegagropila linnaei Marimo Balls rolling back and forth with the waves, just as they do in nature.
4. Laguncularia, Rhizophora and other Mangrove plants.

My current favorite idea for expanding this idea is with a brackish Mangrove setup housing a few trees along with some Cyprinodon, Fundulus or other estuary Killifish. This would require a bigger setup. The little tank I have here is just a 6-gallon and holding only about two gallons of water. Something with a 12" X 48" footprint like a regular 55-gallon could work well as a larger enclosure to include fish.

 

[hydrophyte]

I found something really interesting with slo-mo video showing the machine generating two waves with each stroke. I had previously assumed this was caused by resonance since there is still some sloshing with waves bouncing off the far end of the tank. But the slow-motion video clearly shows the second, slightly smaller wave formed with the paddle up-stroke; with the paddle quickly lifting up into the air, energy just fore and aft combine to create a neat second wave a bit smaller than the main wave.

This kind of wave generation could probably be corrected with a modified cam shape. With a cam flattened on one side, but with a round semi-circle on the opposite side, the up-stroke will be more gradual and probably less likely to generate this second wave. However, it also looks like the second smaller wave is deepening the trough for the next main wave to make a taller wave with more amplitude, so I'm just going to leave this as it is for now.

I probably won't leave it up for long, but you can see the slow-mo in this post on my Instagram, Swipe to the fourth frame for the video....

 

[hydrophyte]

Bookmarking this here before I forget about it....

River Flows - 5ft Bookshelf Tank



Really excellent implementation in this long and linear tank. Unfortunately, it looks like the manufacturer went under and/or changed their name and they no longer offer this 5ft bookshelf aquarium. Although I suppose I could alternatively build one myself. This would be such a nice size & shape to use with a wave machine.

 

[hydrophyte]

New video up with the wave machine and some other context....

Trailer I

 

[hydrophyte]

Last night I cut out parts for the ripple tank mechanism. Stainless #4 machine screws will connect the spring (an RC car shock). Actuation is to be achieved with an off-center mass attached to the front of the brushless gimbal motor. I'll be pleased if this version #1 works even just a little bit.

 

[hydrophyte]

A couple new update pics...

The plants are growing in nicely. I zip-tied a couple of additional manzanita branches into the hardscape. The paddle design is revised and I also cut an acrylic cover for the microcontroller assembly.

 

[hydrophyte]

Finally got the video done. Please watch if you have a couple minutes. If you like it, please like, share and comment...

 

[LondonDragon]

Missed this one, that looks pretty cool indeed 🙂 nice idea and execution, going to add any fish to this?

 

[hydrophyte]

Missed this one, that looks pretty cool indeed 🙂 nice idea and execution, going to add any fish to this?

Thanks so much for stopping by! Please share my video if you can think of any places. YouTube is so saturated with content it's difficult to get very far in there these days.

This aquarium has only about two gallons of water, so it's not really enough for fish. But I'm planning on a wave tank in a 48" enclosure probably with mangrove trees, brackish water and estuary killis or poeciliids.

 

[hydrophyte]

I made a prototype version of the ripple generator. But unfortunately it's totally wrong. With this arrangement, the RC car shock would need to work as an extension spring, but it is a compression spring. Even if the motor could actuate the ripple tank tank paddle a little bit, there would be a maddening click with each stroke. I want to make this mechanism as compact as possible and I had also hoped the spring shock along with the rod + bearing would keep it aligned, but it easily yaws back and forth. So I think it will indeed require a second rod + bearing.

 

[hydrophyte]

Here's another fluid dynamics + physics + aquarium idea. I built a quick prototype for securing a water pump on the bottom of a glass tank with a bare impeller pointed straight up...



This achieves the same thing as many rather cheap "vortex fountains" with impellers stirring at their bases to create rotational water motion and water vortices. Spend some more and you can also find this idea combined with a water pitcher and dubious health claims about "energized" drinking water.

To incorporate into an aquarium, I'll cut that base from black HDPE, rather than white. Here it is in a rather large (almost 5 gallons) glass vase...



With free circular water movement in that cylindrical enclosure, a vortex easily develops in as much as 11" of water depth. An aquarium setup with a few of these spinning inside would be way too energetic for fish or most other livestock as well as live plants, but I do have a couple ideas for integrating live organisms:

1. Freshwater - moss-covered rocks
2. Marine - Coralline algae and other encrusting organisms

As with the water wave machine, the vortex generation will create most of the visual interest for the setup. There is not as direct a connection between water vortices, ecosystem development and evolution as there may be with traveling water waves, although an aquarium setup like this could model tide pools and other highly energized environments with turbulent water motion.

So the idea would be to position several of these in a tank with stones covering the remaining open tank bottom. Obstructing the rotational flow with a few round lava rocks, however, severely impedes vortex generation. I had to lower the water level to within just a couple of inches of the impeller to create a vortex...



By swirling the water with my hand in the same clockwise direction, I was able to encourage the creation of a much stronger vortex....



My next test will involve trying this device in a shallow rectangular tank along with a second water pump with the impeller housing in place and pushing water around horizontally to create water rotation and probably easier vortex generation.

An additional issue is the loud sucking noise and intense air bubble generation whenever a strong vortex contacts the impeller. You would not want the setup to run like this all the time, so it could instead be controlled with on/off switch and/or input voltage control

 

[hydrophyte]

I did another test and this time in a small (19" X 11" X 11") rectangular tank. With a small pump up near the waterline and pushing water around clockwise, the impeller created a strong vortex in 7" of water.



The developing vortex casts this interesting dark round shadow encircled with a bright corona.



I had to lower the water to 4" deep, but I also got vortex generation with the round stones covering most of the tank bottom.



So my idea is to use stones like these planted with either aquarium Mosses (freshwater) or Coralline Algae and other encrusting organisms (marine). Here's the tank I have in mind...

UNS 60S - 10 Gallon Ultra Clear Rimless Aquarium

This would make a nice broad footprint area for a stone arrangement in an enclosure of moderate size.