Chapter 8: Waves Flashcards
what causes most waves?
wind
what is the difference between wave and energy?
Wave- Is the movement of energy
Current- is the movement of water
Describe the different types of waves and their causes?
ocean waves(The movement of air across the water), atmospheric waves( the movement of different air masses), internal waves( the movement of water of different densities), tsunamis(seismic activity), and tides(the gravitational force of the moon).
Describe orbital waves.
waves that have both longitudinal and transverse movement causing particles to move in a circular motion.
What is wave steepness? At what wave steepness do waves break?
Is the ratio of wave height to wave length. H/L. wave break when they reach a steepness of 1/7.
What are wave period and wave height?
wave period- is the time it takes a wave to pass a certain point.
wave frequency- is inversely related wave period and is the number of wave crests to pass a fixed point in a certain amount of time.
What is wave base? where is the wave base?
at some depth below the surface the circular orbits become so small they are negligible. it is equal to half the wavelength or (L/2)
What are the 3 categories of waves based on depth? ( definition and what determines speed)?
Deep-water-If the water depth(d) is greater than the wave base(l/2).speed is dependent on wavelength.
Shallow-water- waves in which depth(d) is less than 1/20 of the wave length. speed is proportional to depth.
Transitional- has properties from both of the previous two and speed is partially dependent on depth and wavelength
Define sea, swell, and fetch
sea- area of water where wind generated waves occur.
swell- uniform, symmetrical waves that originate from sea areas.
fetch-distance over which wind blows.
What factors affect wave energy?
Speed, Duration, and Fetch
What is a fully developed sea?
Maximum wave height and wave length for a particular fetch, speed, and duration of winds at equilibrium conditions.
What is the surf zone?
zone of breaking waves near shore.
Describe in detail what happens when waves approach shore.
Wave speed decreases, wavelength decreases, wave height increases, and wave steepness increases.
