Hydrodynamic Plane Wave Generator

Last crawled date: 4 years, 2 months ago

This is my version of a Hydrodynamic Plane-Wave Generator as designed by:
D. M. Harris, J. Quintela, V. Prost, P.-T. Brun, & J. W. M. Bush
Department of Mathematics, Massachusetts Institute of Technology, Cambridge, USA
E-mail: pierrethomas.brun@gmail.com
Here is a link to their design:https://math.mit.edu/~bush/wordpress/wp-content/uploads/2016/09/JOVI-S-20161.pdf
I basically followed their design with the following changes:
I used an old Dell laptop charger that I had laying around. It outputs 19.5 volts at 4.62 amps.
I used a modular frequency generator (purchase from Amazon in kit form KKmoon XR2206) in lieu of using a cell phone with the frequency generator application. I will be using this in public demonstrations and felt this would be easier.
The frequency generator requires a voltage input from 9-12 volts. I added a voltage buck module (Amazon - any model will do - I got one with a voltage display - button changes display from input voltage to output voltage) to reduce the voltage to the frequency generator to 10.0 volts.
For personal use the cellphone with the frequency generator application should work (frequency generator and buck module would not be required).
The amplifier model I used is "AOSHIKE TPA3116 DC 12-24v 100W Subwoofer Amplifier Board - also from (you guessed it) Amazon.
The speaker is a 6.5" 8 ohm 30 watt scrounged from a friend - Thanks Camilo.
I use linseed oil in lieu of silicon oil specified (easy to obtain). I will be experimenting with other oils.
The oil dish is Amazon:
100 mm Glass Petri Dish, Autoclavable Tissue Culture Plate, Borosilicate Glass, Pack of 2
by Chang Bioscience
The light strip I used is Amazon:
LEDMO LED Strip Lights, SMD 2835 Non-Waterproof LED Strip DC12V 600LEDs 16.4Ft 6000K 15Lm/LED High CRI80 LED Light Strips 3 Times Brightness Than SMD3528 LED Strip White
One amplifier output powers the speaker and the other powers the light strip.
The strobe effect from the light strip effectively stops the bouncing motion of the oil drop and/or shows it bouncing in slow motion. Is it magic or is it science? See the first picture.
Interesting stuff happens both above and below the Faraday threshold. It may be possible to use this as an analogy to demonstrate talbot effects, quantum effects etc. But its also just fun to bounce a drop of oil on an oil surface!
The OpenScad file includes all the pieces as well as the electronic components. Use comments to control what gets displayed or printed.
Adjust the box height for the speaker that you use.
I also started work on a "cover" for the petri dish - the idea being to 3d print a cylinder to accept an "O" ring to seal the oil in the dish for transport or storage. This is not complete yet.
I mounted all the electronics on the outside of the box (I feel this has some educational value). Also I was not sure how warm or hot the components would get during extended use. I have only run it for a few hours at a time so far and all the components and heat sinks remain cool to the touch. It may be possible to mount all the components inside the box with just the knobs protruding - the box may need to be slightly larger to accomplish this - you can move the electronic components around to test other configurations.
I spray pained the bottom of the petri dish dark brown (black would have been better) to help with seeing the drops.
I used 4 small blobs of epoxy (JB Kwik) to mount the petri dish to the speaker cone.
I mounted the speaker to the bottom of the box using 4 small blobs of epoxy (JB Kwik).
I mounted the light ring to the speaker using a bead of Liquid Nails Small Projects Adhesive.
Enjoy.