Title page
Basic wave theory
Deep water waves
Shallow water waves
Waves in water of varying depth
Wave trains
Beach waves
Applets
References
Symbols Legend
Troubleshooting

 

Deep water waves

The behavior of the waves is quite different if the water is deep or if the water is shallow. 'Deep' is generally measured with respect to wavelength. A body of water is deep if the depth h is much greater than the wavelength L. Since L=2p/k we say that the water is deep if kh>>1.

Recall that the motion of our waves is governed by the formulas

yx(x,y,t) = rcosh(k(h+y))
sinhkh
sin(wt-kx)+x
yy(x,y,t) = rsinh(k(h+y))
sinhkh
cos(wt-kx).

If we assume that a body of water is deep and that we are only intested in water close to the surface (-y<<h) then we may make the following approximations.

sinhkh » (1/2)ekh

sinh(k(h+y)) » cosh(k(h+y)) » (1/2)ek(h+y)

<<previous | next>>