Saturday, June 30, 2012

Wave Sculptures

I have always been fascinated by the power of water and by ways to harness it.  I watered my garden in Menlo Park for over a decade by a hydraulic ram that I placed in the creek behind our house.  I generated power for my cabin in Mendocino with a Pelton Wheel that I built from a Honda Civic alternator and a bunch of stainless soup ladles.  I have designed numerous forms of wave power generators (maybe another blog entry), though I have never built one.

A few years ago I moved near the ocean (Rio Del Mar, CA, just below Santa Cruz), and this has revived my fascination with waves.  Also I live in view of the ugliest landmark on the California coast -- the dead hull of the SS Palo Alto, a concrete ship that never went to sea, but was towed here to be a docked casino on the 20's.  The business failed, the hull broke, and the ship sits at the end of a pier, gated off from public access, and stinking of dead fish and seagull excrement.

But... in storms, it occasionally does interesting things with the waves, and this got me thinking...

I am not good at drawing, but I see endless possibilities in my mind, and maybe I could sketch a few of them later, but here is how I think about it...

Water is nearly incompressible, and this causes great shock forces when it hits a rock in the right way.  It is not uncommon for spray to rise more than 10 times the height of incoming waves.  Unfortunately, the same forces break up the walls and cliffs along the shore, so that the best shapes for wave bursts never last very long (except for some famous large blow holes).

But what if the "rock" were engineered to serve just this purpose, with reinforced concrete and durable coatings?  And what if the shapes were perfect curves for compressing and redirecting the force of the wave?  A series of cavities could be placed at intervals along the path of the waves, leading to sequences of jets as waves come in.  Some shapes could be perfect nozzles leading to narrow, far-reaching jets.  Others could be shaped to mix air, making clouds of spray.  Different cavities could be located in range of low and high tides so that behavior would change constantly with the changing tides.  Then there could be one or two really large cavities reached only during storms.  These would be designed to make colossal explosions of spray -- the kind of thing that would bring TV stations out to the shore whenever the weather is really "bad" (good ;-).

I have focused so far on the physics of the problem but, when I imagine the result, it is always a piece of art, a joyful celebration of the power of the ocean and the beauty of water in all its forms.  I want to release the power of waves in the most fascinating, thrilling and beautiful possible manner.

Intuitively I have a sense of what would make good effects.  Beginning with a simple vertical wall, clearly the shape could be deformed to do an increasingly good job at sending all the water straight up in the air.  Or at sending a small amount of the water very high in the air.  And clearly it is possible to focus the energy of a wave by directing it into a converging channel.  And since water is nearly incompressible, very large pressures can be produced by directing waves into a "dead end" chamber.

I have wanted some convenient way to simulate these effects and to produce a library of useful shapes and interesting effects.  I wrote to various professionals in the field of hydrodynamic simulation and they have mostly been uninterested, or they have told me this problem is too intractable.  I don't believe that, and I began to study the Navier-Stokes equations, cellular simulations and the complicated situation where water meets air.  Now while I still don't believe it's intractable, I did decide that I would rather work with actual waves than spend even more time on my computer.

So I built a wave tank in my driveway, 18 inches wide and 12 feet long, with a paddle at one end and a sloping "beach" at the other.  I made a bunch of shapes out of modelling clay.  This was the most fun part.  Modelling clay is about as far from computers as you can get.

Here is a video that shows how a converging shape can quite easily send water up in the air more than ten times the height of the incoming waves...

This was very gratifying of course, but the funny thing about this project is that I have known from the beginning that it will all work.  It is reality in my mind, and I just have to stick to the vision to make it happen.

The next step in motivation was to engage the ocean.  There are all sorts of rules about the beach where I live.  You need permits from the Park Service and the Coastal Commission if you're going to do anything interesting, and these are almost impossible to obtain.  So I figured I would just do it and ask for forgiveness instead of permission.  I set about to design something we could carry out to the surf, and then remove when we were done.

Modelling clay was out of the question, and so was concrete, but I figured I could at least get my toe in the water, so to speak, with a plywood scupture, as long as I made a place to shovel sand in to keep it in place in the waves.

Scupting with a Skil saw is another good vacation from programming.  I thought about this at night and built it all the next day...

It's a very simple converging shape to give some concentration effect, and some ram effect.  It had to sit in the driveway for about a week because we needed low tide in the morning and evening so that we could install it on the sand in the morning, observe it in the waves during the day, and then remove it in the evening.  The thing was heavy, even without sand, so I put a pipe on each side for handles because we had to carry it a fair distance.  Here we are, schlepping it to the water's edge...

If this looks like a funeral procession to you, it apparently also did to a couple of the seaside residents, and we were soon visited by the local gendarmes.  We almost had to abort the mission, except that I took some liberties in quoting a discussion I had had with the district park ranger (he didn't say a flat "no"), and then a reporter from the local newspaper happened by, and quickly took the side that this would be a very cool thing to try.  The ranger left with "Get it gone by sundown", and we filled the outer hull so it wouldn't wash away.

Not much happened at first.  It just sat there, with only the occasional wave touching it, but after an hour we could tell the tide was rising, and in another hour we had our first spout.  Things just got better and better.  At high tide we were getting wavelets about a foot high entering the converger, and we had spouts over fifteen feet high...

As you can see, this was all without ever getting out into the real waves that were bigger than our box.  We shot some video, drank some beer, got sunburned, and made the front page of the Santa Cruz Sentinel...

The next step is more complicated.  We need permission to do something big and, ideally, the funding to do it as well.  I thought these videos would let us breeze through the regulatory commissions, and get some easy funding from Santa Cruz and the Park Service, but not everyone can see how cool this thing could be.  Fact is I have gotten nowhere locally.

It would also be great to do some serious simulations, but I have not been able to get attention from companies that sell hydrodynamic simulation systems, and not even from the fluid dynamics people at Stanford.

Where there's life there's hope...
I've been meditating on the difficulty of enrolling the local officials, software companies, and academics, and I think they are simply the wrong people with the wrong perspective.  While riding my bike the other day, I think i've come up with a "perfect storm" of potential receptiveness to this project;  a small community that encompasses ocean technology, shoreline authority, likely artistic entusiasm, and possibly even some funding.

There are several wave power projects around the world and, for the most part, they are sites that you can go visit, and look at.  You can imagine that they have little lookout platforms with explanatory plaques and PR about the companies and funding agencies. Wouldn't it be cool, and soooo appropriate, to have a wave sculpture installation in view of the observation deck?  A true celebration of the ocean's power and man's creative involvement in it.  These people know how to simulate ocean waves in action, and they probably even have a small fund set aside for PR.

This is the kind of waves we should be working with (note the SUV for scale)...

So, if you know anyone involved in a wave power project, please send them a link to this modest proposal, and maybe we can take it to the next level.