Lecture 8: Wave energy flux Flashcards
1
Q
What is a crest of a wave?
A
- A wave crest is drawn along a line of
same “phase.”
2
Q
Is energy flux in waves conserved?
A
Without wave breaking or wind energy
input, wave energy flux is conserved
c1E1 = c2E2
3
Q
Explain wave shoaling:
A
- Imagine a shallow water wave
propagating towards shore: - Wave speed slows down
- Wave height must increase to
conserve energy flux (shoaling) - Wave length decreases as wave
speed decreases
4
Q
What is Snell’s law for waves?
A
- Waves approaching a beach at
an angle - One part slows down, the other
still original speed. - Eventually, wave becomes nearly
shore-parallel
5
Q
Explain wave refraction on a point (coast)?
A
- Waves approaching a point
- Waves refract to follow bathymetry
- Note convergence of energy
- Headlands concentrate energy
- Shoaling and energy concentration
make larger waves
(concentrates on point)
6
Q
Explain wave refraction on a beach with inlet?
A
- Waves approaching a curved beach
- Waves refract to follow bathymetry
- Note divergence of energy
- Embayments divert wave energy
Disapates around enbayment
An “embayment” refers to a recess or indentation in a coastline that forms a bay, larger than a cove but smaller than a gulf
7
Q
Can currents cause wave refraction?
A
Yes…
- Strong currents also can cause refraction
- With energy flux conserved, waves can
become large!
