17Jan2005 - Progress on the 2nd prototype.
Here is my current prototype. It is 4 feet long, 4 inches wide, and 8 inches deep. I choose 4 feet long because that was the biggest 1/4" thick plexiglass I could buy at Chase Pitken. In addition, if it were any longer it would not fit on my workbench. I made it 4 inches wide because otherwise I wouldn't be able to get my hands in there to get the nuts on the bolts, or to clean it. It is 8 inches deep, because that is how much material I had. In addition, this should be enough to experiment with different water depths.
I assembled it tonight. It has about 150 6-32 bolts. Suprise! Not all the bolts lined up with the holes I had drilled. An interesting problem to solve after one has already put the caulking on. I'm going to let it dry a few days before I try testing it for water tightness. It will be a miracle if it is; I cut the pieces with a circular saw on the floor of the garage. Not exactly a precise system.
I could not figure out a way to make a water-tight top which would still be removable. So I made a false ceiling which is not water-tight. It is adjustable via the two long bolts sticking out the top.
Above is a diagram of what the false ceiling is for. I want to try having two non-mixing fluids of different densities. I'm hoping for slow-motion waves. However, my experience with prototype 1 showed that if you have no top to the tank, all the waves happen on the air-surface, and you don't get any slow motion. The false ceiling should be similar to having a tank with an adjustable depth.
Will mineral spirits eat the plexiglass and/or the silicon caulking? It didn't seem to hurt prototype 1 in the short time I left the stuff in it. Maybe I just let some sit for a few days to see what happens.
23Jan2005 - Tsunami Tests
Got the tank's minor leaks fixed. First I tried generating some tsunamis with regular water, since I didn't know if the mineral spirits would destroy the tank. Here are the results.
To see an animation with a tsunami in action, Click Here.
This works, and most of the features of the tsunami are there. It just isn't very impressive looking.
With regular water waves, the water does not reach anywhere near the high ground no matter how large I try to make the waves. The tsunami effect only happens when the distance from the wave peaks is much larger than the depth of the water. I.E. a shallow water wave.
To see the video of a non-tsunami, Click Here.
2 Fluid Tsunami Tests
The main problem with the water-only tsunami is that it just goes by too fast. How can we make it go slowly so we can see what happens better? I put water in the tank and color it blue, then add mineral spirits on top. The two don't mix, and the mineral spirits liquid is transparent. Since the water is denser, it sinks. So you have a very strange surface between the two fluids which looks like water surface, except is shinier.
To see the 2 Fluid Tsunami in action, Click Here
So the Tsunami worked, and the motion was nice and slow, but the surface tension of the water really prevents it from looking like a beach. I don't know if anything can be done to reduce the surface tension of the water.
Damage to the Proto 2 Tank
Unfortunately, the mineral spirits turned my GE Silicon II caulking into a jelly-like substance. The tank didn't leak when the mineral spirits was in it. However, after I had drained the tank and tried refilling it with plain water, the caulking was falling out of the seams, and it leaked quite badly after a few minutes. I'm trying to re-caulk it now.
What to do next
To really demonstrate the difference between regular waves and a tsunami, the beach must look like something. Just tilting the tank, and calling the bottom of the tank 'the beach' just doesn't cut it. What I would really like is a tank that is 8 feet long, but that won't happen any time soon. Instead I will have to think about keeping the tank level but making a beach out of concrete. I will not be able to try any more experiments with mineral spirits on this tank, since it destroys the water seal.
The two main problems I'm facing:
1.) The water-only tsunamis are way too fast. The whole think is over in seconds and it doesn't look like much unless you know what you are looking for.
2.) The 2 fluid tsunamis are more impressive, but the surface tension really ruins the realism, and will make any beach-scene with little buildings look silly.
24Jan2005 High hopes
from a research paper: http://db1.wdc-jp.com/isij/pdf/199706/is370557.pdf
I've been investigating other liquids for use with the slowed down version. Silicon oil is non-toxic, has a viscosity less that water, which is extremely important for propagating waves. And it is totally imiscible with H2O. The other good point is that it will not destroy my simulator tank. However, it is expensive. $50 for 1 gal, or $206 for a 5 gal container was the cheapest I could find. It turns out that DOT5 brake fluid is silicon oil, so I'm going to try and get some at Western Auto today. $8 per pint! Obviously I won't be buying enough to do a tsunami until I do the testing with the pint of fluid.
Also, I like the fact that the surface tension is 1/4 that of water. That makes it more likely that I will be able to get a real-beach like looking thing.
With a density of 818, the water will sink to the bottom, much like the mineral spirits. That is good, because it is much easier to dye the water than the silicon fluid.
If it works, I can order some pure silicon lubricant from Kano Labs:
Another option is Molten Iron. The density is a little high, and the surface tension looks fearsome. Also, I'm worried about the fact that it is opaque and the temperature of 1600 degrees C might also damage the simulator tank.
Things are looking up for the slow-motion simulator.
Research into Scale Model buildings etc
The following table shows the scale factors for model railroading. N-gauge looks like a typical building would be 3 cm high. I guess I would like smaller stuff, maybe Z gauge.
SCALE SCALE to FOOT PROPORTION
O(17) .266"(6.75mm) 1:45.2
O,On3,On2 .250"(6.35mm) 1:48
S,Sn3 .188"(4.76mm) 1:64
OO 4.0mm(.1575") 1:76.2
HO,HOn3,HOn2 3.5mm(.1378") 1:87.1
TT, TTn3 .100"(2.54mm) 1:120
N, Nn3 .075"(1.90mm) 1:160
Z .055"(1.39mm) 1:220
I think that Z-gauge is what I will need. There are plenty of N-gauge scenery sources out there, but I could not find any Z-gauge buildings for sale. The one company that seemed to have alot of Z-gauge was Marklin. The closest distributor was a company in East Rochester. I will maybe call them during the week.
http://www.djunction.com/contactus.htm
The Surface Tension Problem
I have read in several places on the net that a drop of soap in the water will reduce the surface tension.
I tried it in a glass dish to see if that will reduce my problem in the two-fluid system. It appeared to help a great deal, but it does tend to make bubbles now. This may not be so bad, because the sea has bubbles when the water is turbulent.
No Soap:
With plain water & Mineral Spirits. To see video, Click Here
With a drop of soap, I think it looks much better. To see video, click here.
Isopropyl Alcohol + Mineral Spirits = Cloudy
