Waves Flashcards
What are the 4 disturbing forces of waves?
- Wind creates capillary waves and surface gravity waves
- Earthquakes create tsunamis
- Landslides created splash waves
- Gravitational pull of moon and sun creates tides
What are the restoring forces of waves?
- Surface tension for capillary waves
- Gravity for all other waves
Name the top and bottom of a wave
Crest
Trough
What is wave period (T)?
Amount of time required for two crests to pass a point
What is frequency (f)?
The number of waves that pass a point period
Ex. If 10 waves move past a point in 100s, then f is (10 waves/100 sec) or 0.1s-1
F=1/T
How to find wave steepness?
Wave height (H)/wavelength (L)
What waves have the lowest frequency?
BIG ONES
What makes the forward motion of water particles in orbital waves?
Stokes Drift
What happens to orbital size and motion with decreasing depth?
It diminishes size and motion
Where is Stokes Drift important?
Why?
Near the shore, because open ocean doesn’t have much forward motion.
At shore, it pushes water up against coast = currents in surf zone
What waves move through water deeper than L/2, and are unaffected by the seabed?
Deep-water waves
What waves move through water shallower than L/20, and are strongly affected by the seabed?
Shallow-water waves
- orbitals get flattened until they just move back and forth
What 4 factors affect size of waves?
- Wind speed
- Wind duration
- Fetch (distance/width the wind blows over water - can make big waves)
- Original sea state (if rough can build up larger waves faster)
What characterizes wind speed?
The Beaufort Scale (chart)
What do you need to calculate celerity?
Water depth and wavelength
