The Naked Scientists

The Naked Scientists Forum

Author Topic: Water waves  (Read 3334 times)

Offline Aquila

  • First timers
  • *
  • Posts: 7
    • View Profile
Water waves
« on: 22/01/2008 17:41:44 »
Why does the speed of shallow water waves decrease as the water depth decreases?


 

Offline JimBob

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 6564
  • Thanked: 7 times
  • Moderator
    • View Profile
Water waves
« Reply #1 on: 22/01/2008 21:59:47 »
It doesn't. Speed increases.
 

lyner

  • Guest
Water waves
« Reply #2 on: 23/01/2008 22:12:07 »
Correct. That's why waves break when they come ashore.They are going too fast for the water depth and fall over themselves.
 

Offline JimBob

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 6564
  • Thanked: 7 times
  • Moderator
    • View Profile
Water waves
« Reply #3 on: 23/01/2008 22:36:34 »
Ah, an oceanographer in the making answering the question! BRAVO!
 

Offline daveshorts

  • Moderator
  • Neilep Level Member
  • *****
  • Posts: 2583
  • Physics, Experiments
    • View Profile
    • http://www.chaosscience.org.uk
Water waves
« Reply #4 on: 24/01/2008 10:52:55 »
According to this:
http://www.seafriends.org.nz/oceano/waves.htm

The speed of a wave in shallow water (where the depth is less than the wavelength) is proportional  to the square root of the depth of the water.

In a wave the water particles move in little circles or ovals, in shallow water for the same wave height the particles have to move further, so the effective inertia of the system is higher so the wave speed is lower.



In the deep water more water can move less far to produce the same effect, this takes less time so the wave moves faster.
 

lyner

  • Guest
Water waves
« Reply #5 on: 24/01/2008 18:04:46 »
Ah, an oceanographer in the making answering the question! BRAVO!
A little anthropomorphism never did anyone any harm!
 

The Naked Scientists Forum

Water waves
« Reply #5 on: 24/01/2008 18:04:46 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums