Freak%20Waves%20and%20Wave%20Breaking%20-%20Catastrophic%20Events%20in%20Ocean - PowerPoint PPT Presentation

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Freak%20Waves%20and%20Wave%20Breaking%20-%20Catastrophic%20Events%20in%20Ocean

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... Andrey Pushkarev [2,4], Alexander Prokofiev [3,4] and Alexander Korotkevich [1,3] ... There are two types of rare catastrophic events on the ocean surface: ... – PowerPoint PPT presentation

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Title: Freak%20Waves%20and%20Wave%20Breaking%20-%20Catastrophic%20Events%20in%20Ocean


1
Freak Waves and Wave Breaking -Catastrophic
Events in Ocean
  • V.E. Zakharov 1,2,3,4
  • in collaboration with Alexander Dyachenko 3,4,
    Andrey Pushkarev 2,4, Alexander Prokofiev 3,4
    and Alexander Korotkevich 1,3
  1. University of Arizona
  2. Lebedev Institute for Physics
  3. Landau Institute for Theoretical Physics
  4. Waves and Solitons LLC, W. Sereno Dr., Gilbert,
    AZ, 85233, USA

2
Let elevation of ocean surface. In
the first approximation this is quasi-stationary,
quasi homogeneous random process, close to
Gaussian.
3
  • There are two types of rare catastrophic events
    on the ocean surface
  1. Freak waves (major catastrophic event)
  2. Wave breaking (minor catastrophic event)

Freak waves are responsible for ship-wreaking,
loss of boats, cargo and lives. Wave breaking is
the most important mechanism of wave energy
dissipation and for transport of momentum from
wind to ocean.
Analytic theory is for both of these are not
developed
4
New Year wave 1995 year
Extreme wave in the Black sea 2002 year
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Freak waves program for future.
We are planning to perform massive numerical
simulation of different stationary wave spectra
to determine dependence of probability of freak
wave formation on energy spectrum. Measuring
of energy spectrum is a relatively easy problem.
It will Make possible to estimate a danger of
freak wave appearance in a given place in a
given time
24
Wave breaking
Evolution of the surface waves spectra is
described by the Hasselmann kinetic equation
Here nothing but the standart quantum
kinetics equation for Boson-type Quasiparticles
in the limit of large occupation numbers.
- nothing but the standart quantum
kinetics equation for Boson-type quasiparticles
in the limit of large occupation numbers.
- dissipation due to wave breaking.
we should have an adequate theory of atmospheric
boundary layer
To find
over ocean. This boundary layer is badly
turbulent.
25
we need the theory of wave breaking. It is not
developed yet.
To find
But we can perform a numerical experiment
should be the same in both equations. The
instability growth rate was
26
Magnified surface shape Y(x) for time t2994
(start of run-off)
27
Surface shape Y(x) for time t2994 Similar scale
for both axes
28
H(t)
29
Steepness µ(t), smoothed
30
Particular experiment
t
31
Approximation of function
(numerical values obtained by least squares
method)
32
Program
Development of these experiments will make
possible to determine in a reliable way
and improve essentially quality of
wave-forecasting models.
Then from comparison with experimental data we
will be able to estimate which model of
is closer to reality.
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