Chemistry Reference
In-Depth Information
(a)
1
2
0
2
4
6
8
10
12
14
16
(b)
50
40
1
2
30
0
2
4
6
8
10
Wavenumber, rad/cm
Fig. 3.
Frequency spectra
(a)
and phase velocities
(b)
of wind waves at two
fetches (
1
- small fetch,
2
- large fetch). Clean water, wind velocity 2.5 m/s. Solid
line in Fig. 3b - phase velocity for linear gravity-capillary waves (surface tension
72 mN/m) accounting for wind drift
3.2 Contaminated water surface
Wave damping due to a film is characterized by the contrast
K(k) =
F
nsl
/F
sl
, where
F
nsl
and
F
sl
denote the spectra of wind waves in non-slick
and slick regions at a given wave number
k
. The contrasts and the phase
velocities measured by the optical spectrum analysers are presented in
Figure 4 for the case of “large fetch/film 1” and in Figure 5 for the case of
“small fetch/film 2”. The contrast curves in Figures 3 and 4 show the oc-
currence of the maximum, which corresponds approximately to wave-
lengths of about 6-8 mm, which are typical wavelengths of parasitic capil-
lary ripples (Ermakov 1986). The wavelengths of the contrast maximum
