WATER WAVE DYNAMICS AND THE SECRET OF THE TSUNAMIS

1
WATER WAVE DYNAMICS AND THE SECRET OF THE TSUNAMIS

• Presenters
• -Isaac Katz
• -Zsuzsanna Kis
• -Kinneret Rozales
• Mentor Ronen Avni
• Location Haifa, Technion city, Faculty Of Civil
  Engineering.

2
THE PHYSICS OF WAVES
The following mathematical equation, commonly
referred toas the wave equation served as the
scientific foundation for this work.Its
derivatives are also here shown, although for
shortness of spacenot explained.These basic
equations have uncovered the firsts steps
towardsan understanding of fluid dynamics in
general and water-wavebehavior in particular and
I think them crucial for any one to knowwho has
an interest in this subjectespecially as they
dont require advanced education to understand.
3
WATER-WAVE EQUATION AND ITS DERIVATIVES
4
WAVE SPEED EQUATION
Long waves are non-dispersive Their wave speed
is independent of their period.It depends only
on the water depth, in the form ( c is wave
speed, h water depth, g gravity).
The velocity structure in a long wave is
described by
where z is the time dependent surface elevation
(wave amplitude)and u the horizontal particle
velocity. It follows that u is independent of
depth and the vertical particle velocity varies
linearly with depth. Particles move on very flat
elliptic paths in nearly horizontal motion.
5
WAVES IN THE LAB
We can see examples of waves all around us, Here
we experiment with many objects to find out their
properties And see how they relate to waves.
Using a pendulum, a moving board and some sand we
can see the interesting results that show us
howthe same underlying sinus wave shapeforms on
different situations and materials.
6
And here we can see a wave forming from
the rhythmical up and down movement of a spring
rope. The faster the rope is moved the more waves
are formed, with nodes and anti-nodes developing
harmoniously with the movement, we can thus see
the rope evolving from a single waveform into
multiple, complicated patterns which are not
always symmetric.
A demonstration of waves with normalconditions
approaching a shoreif looked at closely one
candistinguish de similarities of the basicwave
form with the picture in the right.
7
WHAT DOES TSUNAMI MEAN?

• Japanese word which in English means Harbor Wave
• Commonly known as tidal waves
• Composed of a train of waves

8
CHARACHTERISTICS OF TSUNAMIS

• Long wave periods
• Can achieve extreme heights
• Are rare events
• At open sea, they travel extremely fast, reaching
  velocities of 700 Km/H (400 Mh/H)

9
WHAT CAUSES TSUNAMIS

• Sub-marine earthquake
• Landslides
• Volcanic eruptions
• Cosmic body impacts (asteroids, comets, etc.)

10
WHAT HAPPENS TO A TSUNAMI AS IT APPROACHES LAND

• Its height grows due to shoaling
• They lose some energy as they rush onshore
• Depending on the particular beach this makes
  surfing possible

11
SPECULATION ON A MASSIVE TSUNAMI

• If an asteroid or comet 4 kilometers in diameter
  were to strike the earth the resulting wave can
  make entire coastlines disappear and wreck havoc
  on national infrastructures. If the body were
  large enough, it would achieve the status of ELE
  (Extinction Level Event) and change our
  fundamental way of life

12
THE IMPACT ON HUMANS

• Tsunamis are considered catastrophic events
• They are rare, but very difficult to predict
• The death tolls of an attack can reach tens of
  thousands

13
WAVE RESONANCE
An interesting wave phenomenon is the resonance
effect that occurs whena tsunami, or any other
type of wave, comes into indirect contact with
anothermedium which has the same properties and
part of its energy is transferred tothe other
medium, thereby resonating itself into places
which otherwise itwould have been impossible to
enter.
14
WAVE SUPERPOSITIONS
The following mathematical equationsexpresses
the processes of wave superpositionswhen two
waves come together and form a singleone with
characteristics of both.In the picture we see an
electronic wave simulatorwhich is showing this
kind of phenomenon.
15
THANKS

• Ronen Avni for teaching us so very patiently the
  material and for his great examples.
• Technion for letting us use their facilities
• Faculty of civil engineering
• Ami and Guy for driving us around and help