Monday, January 08, 2007

Wave Energy

Vero Beach

We're working on several small projects while waiting for the engine. I put in a new shore battery charger. We're repainting the non-skid areas on the deck, refinishing the bowsprit, and we're going to paint the anchor chain. I'll write each of these up in the blog as they get completed.

Both yesterday and today we spent part of the day at the beach. The weather has been very warm so the beach sounded nice. Besides that, Vero has a nice beach and it's only a mile away.

Today, on the advice of other cruisers, we took the dinghy north and east of here into a network of canals and fancy waterfront houses. About a mile away there is a public park where we could beach the dinghy. Across the street from that is the town beach. It's all very pretty and nice.

The sea water temperature was (I think) warmer than average for this time of year. One could stay in the water for a half hour or more without getting chilled. I did exactly what I liked doing as a kid. I stood in the water up to my waist and let the breaking waves wash over me. Boys of all ages like doing that.

Today I was wondering about all the energy dispersed as waves break on a shore line. Waves we know carry lots of energy and all of it must be dispursed as heat on the shore. When the surf is high, it would seem that the water close to the beach should be warmer than the water temperature further out. Is that because the energy is small, or because the mixing with offshore water is so great?

That made me wonder further how to calculate the energy in a single wave, or the power of a series of waves. There was a time when I was a fresh engineering graduate that I probably could have calculated that using only the Handbook of Chemistry and Physics as a reference. I sure couldn't do that today. I bet my friend John Undrill could still do it. John is one of those guys scoring 100% on his professional engineering exam more twenty years after graduation. (John, would you like to do the wave calculation for me now?)

My favorite physics problem was what I called the teapot problem. After several years simulating the dynmics of boiling water nuclear reactors, I became very involved with the physics and the dynamics of the problem. I even remember dreaming about it, visualizing the steam bubbles in the boiling water expanding as they approached the surface. Actually, a teapot is a bad analogy; a reactor is like a pressure cooker.

I remember having a very elegant closed form solution for the dynamic equations based only on first principles -- mass, energy and volume balances. It worked fine unless the gas and liquid phases were not the same temperature. I could never find any physics or experimental information on the heat transfer for a (boiling) liquid - gas surface. It also didn't work if there were any non-condensible gasses (like air) in the vessel.

No comments:

Post a Comment

Type your comments here.