NOTES
Links to summaries of key issues for each topic
VISUALS
Links to images employed in lectures on a topic-by-topic basis
TEXT
Link to chapter outlines at online learning center at McGraw Hill.
NOTES
Links to summaries of key issues for each topic
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Ocean Wave Dynamics and Wind Waves
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Notes on Topic:
The notes represent summaries
of key issues for each topic
They emphasize the terminology used to
describe the various phenomena.
| 3. Shallow-Water Waves |
| Learning Objectives: |
- Appreciation of changes in waves characteristics as they enter shallow
water
- Understanding of behavior of waves approaching shore, or meeting obstacles
- Recognition of processes associated with breaking waves on shoreline
- Understanding that waves can occur at the boundary of
distinct layers
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| Characteristics of Shallow-Water Waves: |
- Water parcels affected by bottom as water shallows
- begins when depth (D) < L/20
- orbits become elliptical
- waves slow down
- wavelength decreases as height increases
- kinetic energy converted into potential energy
- when steepness reaches = 1/7, waves begin to break, breakers.
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| Refraction, Reflection and Diffraction: |
- Refraction:
- crest lines approaching shore at an angle are rotated
- result is wave refraction as waves slow in shallow water
- wave rays (lines perpendicular to wave crests) reflect energy
- wave energy is focused on headlands, dispersed in bays.
- Reflection:
- caused by smooth straight barriers
- e.g. cliffs, breakwaters.
- Diffraction:
- created by wave movement through narrow openings
- can form interference patterns.
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| Surf Zone: |
- Breakers: band of breaking waves on shorelines creating surf.
- Types:
- plunging, on narrow, steep beach slopes
- spilling, on wide, flat shores
- curl starts in shallow water creates tube
- uniform waves often from swell.
- Water Transport:
- seaward return of water focused at specific points
- creates rip currents; stirs sand, forms turbid water.
- energy release as spray
- may send water high up beach, especially during storms
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| Internal Waves: |
- Waves at depth
- at the interfaces of different density layers
- move slowly, may break mixing layers.
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Department of Geological Sciences,
1001 E. Tenth Street, Bloomington, IN 47405-1403
Phone: (812) 855-5582 Last updated: 7 December 2000
Comments: simon@indiana.edu
Copyright
2000, The Trustees of Indiana University
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