Wednesday, October 03, 2007

What wave is dangerous?

I consider myself easily get excited, but I have not gotten excited for quite some time. I think I am just now getting excited on reading this brief UPI Science news yesterday:
ANN ARBOR, Mich., Oct. 2 (UPI) -- Everyone knows big waves in fierce storms are dangerous, but now U.S. scientists are discovering smaller waves might be just as threatening.

University of Michigan researchers have developed a computer program and method of analysis that makes it easier to understand how a series of smaller waves -- a situation much more likely to occur than the development of monster waves -- might be just as dangerous.

"Like the Edmund Fitzgerald that sank (on Lake Superior) in 1975, many of the casualties that happen occur in circumstances that aren't completely understood, and therefore they are difficult to design for," Professor Armin Troesch said. "This analysis method and program gives ship designers a clearer picture of what they're up against."

Troesch and doctoral candidate Laura Alford presented their findings Tuesday in Houston during the International Symposium on Practical Design of Ships and Other Floating Structures, also known as PRADS 2007.
The idea that "a series of smaller waves . . . might be just as dangerous" is what refreshingly new, no one has ever considered and paid attention, and could be leading to exciting new researches that has not come to light for a long time. Some further introduction of their method can be found in this U. Mich. Press Release:
Today's ship design computer modeling programs are a lot like real life, in that they go from cause to effect. A scientist tells the computer what type of environmental conditions to simulate, asking, in essence, "What would waves like this do to this ship?" The computer answers with how the boat is likely to perform.

Alford and Troesch's method goes backwards, from effect to cause. To use their program, a scientist enters a particular ship response, perhaps the worst case scenario. The question this time is more like, "What are the possible wave configurations that could make this ship experience the worst case scenario?" The computer answers with a list of water conditions.

What struck the researchers when they performed their analysis was that quite often, the biggest ship response is not caused by the biggest waves. Wave height is only one contributing factor. Others are wave grouping, wave period (the amount of time between wave crests), and wave direction. "In a lot of cases, you could have a rare response, but when we looked at just the wave heights that caused that response, we found they're not so rare," Alford said. "This is about operational conditions and what you can be safely sailing in. The safe wave height might be lower than we thought."
In this era of faster and faster computers with larger and larger storages, computer modeling is relatively easy and convenient to do. But good new ideas even in the academe are considerably rare and hard to come by. I congratulate Prof. Troesch and his students for this new endeavor. As indicated in their press release, it is expected to help spur innovation. I think that's what most certainly will leading to. I don't think their new approach will nullify freaque wave as we know it, especially the freaque waves that happen during calm conditions. But I think they may provide alternate viewpoints regarding whether or not the claim of freaque waves during storm conditions is veracious. Ever since the discovery of the recording of a freaque wave on the North Sea Draupner Platform on 1995 New Year's day, the freaque wave community and the media at large have been all but predetermined most of the ship sinking disasters were resulted from large monster waves, mostly unknown and without substantiation. Now for the first time we have seen creditable indications that those are not necessarily only because of the largest waves.

Let the spur of new innovations begin!

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