Powerhead mod / experiment idea

[MrJoel]

I am thinking about trying to make a mod for my Hydor powerhead.  I have been exploring some ideas to make the flow more irregular and came up with the idea to put and bead on a length on line attached to the cross in the middle of the powerhead output to induce karman vortices in the flow downstream from the bead suspended in the flow from the powerhead. 

In searching for similar setups I cannot find any references , so I thought I would bounce the idea off you fine folks. 

I will probably experiment with bead size and string length for the anchor to find a sweet spot for my tank. But I think the disruption in water flow created by inducing karma sheeting in the flow would help me get better dispersion of flow in the tank. 

I may also experiment with using several lines to see the difference in flow between a stable multipoint anchor position and the single central anchor which should cause the sphere to vacillate in the stream like a pendulum to further disrupting the flow.

Maybe I should pull my kids in on this too and then they can document and prepare for their science fairs next year. =)

 

Any thoughts?

[SaltyBuddha]

Interesting. In theory, the karman shedding should create more of a wave or pulsing action behind the bead. I think you might need something a little bigger than a bead to have a large enough effect though, maybe a marble?

 

You would probably need to stabilize the bead (or marble) as well. The flow from the powerhead is not going to be completely laminar in the tank. On a string, I could see the bead doing a lot of fluttering. Imagine fans with ribbons. Those things go all over the place. Putting the bead on a fixed pole could solve that issue and make the wave action much more regular. Definitely would need fixed poles if you want multiple beads.

[MrJoel]

8 minutes ago, SaltyBuddha said:

I think you might need something a little bigger than a bead to have a large enough effect though, maybe a marble?

Beads vary in diameter I have seen some up to 1/2 to 1".  I am thinking a 1/3 -1/2" sphere.  The material density would be a factor. Originally I was thinking about using a mini drill bit on an acrylic sphere but I suspect the acrylic could be too heavy to stay suspended in the stream. I looked at acrylic , plastics and aragonite. I will probably test a few. I need one that will remain in the flow and is a material that will be reef safe longterm.