Plastic Beach - Traveling Water Wave Machine

[rhizotron]

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.

 

[rhizotron]

A couple new update pics for the wave machine....

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

 

[rhizotron]

I must be the world's slowest video editor. But I finally got this thing done. Please watch if you have a couple minutes. If you like it, please like, share and comment...

 

[rhizotron]

I assembled the prototype version ripple generator. But unfortunately it's totally wrong. With this arrangement, the RC car shock would need to work as an extension spring, but positioned above the gimbal motor it is instead 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.

This was OK though just for thinking this through some more and seeing how the parts would go together.

 

[rhizotron]

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. A small 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, a much stronger vortex was created....

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

 

[rhizotron]

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...

https://buceplant.com/collections/u...ns-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.





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[rhizotron]

I got the FOC driver in the mail and soldered the pins in place. I hope I can get this to work with that brushless motor for the ripple tank concept...

As mentioned above, I have my eye on the Ultum Nature System 60S aquarium. This tank has a cool broad + shallow (23.62" X 14.17" X 7.09") shape and I think it might work well with either the ripple tank or the vortex aquarium idea, or both. I also a concept in mind for a concrete stand and made a quick CAD sketch. This would require a very simple concrete mold with just some pieces of plywood comprising a box within a somewhat larger box and the concrete mix poured into the space between them...