Waves And Water Dynamics

disturbing force - the energy that causes ocean waves to form- wind blowing across ocean surface- movement of fluids with different densities (waves travel along the interface between the two) ocean waves - along an air-water interface, the movement of air across the ocean surface creates ocean waves internal waves - water-water interface- movement of water of different densities- can be much larger than surface waves, but aren't as energetic- created by: tidal movement, turbidity currents, wind stress, passing ships pycnocline - a layer of rapidly changing density- associated with internal waves seismic sea waves/tsunami - caused by sea floor movement: - turbidity currents- volcanic eruptions- fault slippage progressive waves - waves that oscillate uniformly and progress or travel without breaking - longitudinal, transverse, orbital longitudinal waves - push-pull in the same direction that the energy is traveling- shape of the wave (waveform) moves through the medium by compressing and decompressing- energy can be transmitted through all states of matter transverse waves - energy travels at right angles to the direction of the vibrating particles- transmit energy only through solids orbital waves - interface waves- involves components of both longitudinal and transverse waves- move in circular orbits still water level - halfway between the crests and troughs- zero energy level- level of the water if there were no waves wave breaks - the wave is too steep to support itself- anytime the 1:7 ratio is exceeded (along shoreline or out at sea)- Ex:wave 7m long can only be 1m high frequency - the number of wave crests passing a fixed location per unit of time- inverse of the period circular orbital motion - as a wave travels, the water passes the energy along by moving in a circle- wave itself doesn't travel the entire distance, but the waveform does wave base - equal to one half the wavelength (L/2) measured from still water level- circular orbits become so small that movement is negligible deep-water waves - water depth (d) is greater than the wave base (L/2)- have no interference with the ocean bottom Celerity (C) - wave speed - wavelength (L)/period (T)- the longer the wavelength, the faster the wave travels- depends only on wavelength shallow-water waves - depth (d) is less than 1/20 of the wavelength (L/20)- long waves- ocean floor interferes with their orbital motion- speed is only influenced by gravitational acceleration and the water depth (gravitational acc. remains constant on Earth)- particle motion is in a very flat elliptical orbit that approaches horizontal (back and forth) oscillation transitional waves - intermediate waves- characteristics of shallow and deep water waves- wave speed depends partially on water depth and partially on wavelength capillary waves - small, rounded waves with V-shaped troughs- wavelengths less than 1.74 cms- capilarity is the dominant restoring force that works to destroy these waves, to smooth ocean surface gravity waves - symmetric waves- wavelength exceeding 1.74 cms- gravity is dominant restoring force- wave height increases more rapidly than wavelength; crests become pointed and troughs rounded- results in a trochoidal waveform sea area ("sea") - area where wind-driven waves are generated factors that determine the amount of energy in waves 1) wind speed2) duration - length of time during which the wind blows in one direction3) the fetch - the distance over which the wind blows in one direction fully developed sea - equilibrium condition- waves can grow no further because they lose as much energy breaking as white-caps under the force of gravity as they receive from the wind swells - uniform, symmetrical waves that have traveled out of the area where they originated- move with little loss of energy, transporting energy away from one sea area and depositing it in another shoaling water shallow water physical changes as deep-water waves of a swell move toward continental margins - wave speed decreases- decrease in wavelength- wave height increases- increase in wave steepness (H/L) until 1:7 ratio and wave breaks as surf wave refraction - as a wave approaches shore at a slight angle to the shore, some segment of the wave will "feel bottom" first and will slow before the rest of the wave- the bending of each wave crest as the waves approach the shore- refraction of waves along an irregular shoreline distributes wave energy unevenly along the shore orthogonal lines - wave rays- are drawn perpendicular to wave fronts and are spaced so energy between lines is equal at all times- help show energy is distributed along the shoreline by breaking waves- converge on headlands - heavy erosion- diverge in bays - deposition wave diffraction - results from wave energy being transferred around or behind barriers that impede the wave's forward motion- any point on a wave front is a source from which energy can propagate in all directions standing waves - produced when waves are reflected at right angles to a barrier- the sum of two waves with the same wavelength moving in opposite directions, resulting in no net movement (no circular motion)- nodes - lines along which there is no vertical movement- antinodes - crests that alternately become troughs