Re: freak waves

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: I remember seeing something on either the Discovery Channel or the Learning Channel about the proportion of freak giant waves to normal ones. I think that I remember that they come in three sizes and the largest ones are the rarest. I don't remember the proportion, but it seems that it was some mathematical progression. I tried to find it, but only came across an abstract of a paper on the subject (p.113 of Vol. #355, 1998): : Journal of Fluid Mechanics (1998), 355:113-138. Cambridge University Press. : Copyright © 1998 Cambridge University Press : -------------------------------------------------------------------------------- : On the chance of freak waves at sea : -------------------------------------------------------------------------------- : BENJAMIN S. WHITE a1 and BENGT FORNBERG a2 : a1Exxon Research and Engineering Co., Route 22 East, Annandale, NJ 08801, USA : a2Department of Applied Mathematics, University of Colorado at Boulder, Campus Box 526, Boulder, CO 80309-0526, USA : (Received October 28, 1996; Revised July 4, 1997) : Abstract : When deep-water surface gravity waves traverse an area with a curved or otherwise variable current, the current can act analogously to an optical lens, to focus wave action into a caustic region. In this region, waves of surprisingly large size, alternatively called freak, rogue, or giant waves are produced. We show how this mechanism produces freak waves at random locations when ocean swell traverses an area of random current. When the current has a constant (possibly zero) mean with small random fluctuations, we show that the probability distribution for the formation of a freak wave is universal, that is, it does not depend on the statistics of the current, but only on a single distance scale parameter, provided that this parameter is finite and non-zero. Our numerical simulations show excellent agreement with the theory, even for current standard deviation as large as 1.0 m s-1. Since many of these results are derived for arbitrary dispersion relations with certain general properties, they include as a special case previously published work on caustics in geometrical optics. : Article Text(1420 Kb) : : : Did anyone hear about the rogue wave yesterday that hit that Navy destroyer? Happened out in the Pacific. Don't know why it's not on the news. After that 7.7 I checked the tsunami page. No warning issued. Not sure WHAT this was but had to be one mighty wave to hit a destroyer and cause injuries. The Coast Guard was transporting the injured off the destroyer to bay area hospitals. By calculations a tsunami should have hit their area about 14 hours post quake. By about 1am not 9am as it hit this ship. Any thoughts of facts about this? Lucinda : : : Mary Maya

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