Waves Flashcards
Transverse?
90 degrees
Longitudinal?
180 degrees
Generating force of waves?
wind, storms, earthquakes, sun and moon
Restoring force of waves?
gravity, surface tension
What does the wave form depend on?
wind speed, duration, fetch (distance over which the wind blows), original sea state.
What happens when there is a large fetch and duration?
size of wave depends only on wind speed
fully arisen sea
Hs = 0.025 u^2
bigger the speed, bigger the wave
What does Hs mean?
Significant wave height - average height of the highest 1/3rd of the waves
Particle motion beneath the waves in deep water?
wave particle orbits are circular, forwards beneath crest and backwards beneath trough
Particle motion beneath the waves with negligible depth > wavelength / 2?
Particle orbits are closed
no net flow of water
energy and momentum transferred by the waves.
What is Stokes drift?
At the surface for large waves the particle orbits are open and the netflow of water is known as stokes drift.
Particle motions in shallow water?
Particle orbits are influenced by the sea bed and often compressed in the vertical motion to ellipse
What is shallow water classified as?
depth < wavelength / 20
What is the life of an ocean wave?
storm winds - unsteady, variable direction
waves generated are - forced waves, irregular, mixed characteristics, known as ‘SEA’
How is swell produced?
Longer waves travel faster running ahead of shorter waves.
How do you calculate the wavelength?
L = gT^2 / 2 pi
