Chemistry Reference
In-Depth Information
Fig. 1.
Curvature spectrum
B
(
k
) according to the present model for wind speeds
U
10
= 2, 4, 6, 8, 10, 15 m/s (lower to upper curves). Wave age is 25, no slick
Figure 3 shows the effects of a slick. As a typical example, the visco-
elastic parameters for oleic acid (|
E
s
| = 0.014 N/m,
į
s
= 176°) were used
(Alpers and Hühnerfuss 1989). The friction velocity
u
*
was lowered to
80 % of its clean surface value (Alpers and Hühnerfuss 1989), but disap-
pearance of the surfactant as a result of mixing due to the sea state was not
taken into account. It can be seen that the effect of the slick is most pro-
nounced at shorter wavelengths, waves with
k
> 100 rad m
-1
being very
strongly suppressed. In the saturation/gravity range the spectral intensity is
lowered but the curvature spectrum remains flat. This can be understood
because this range of the spectrum (up to where the Marangoni damping
M
first begins to come into effect) is directly set by the boundary value
İ
(
k
0
),
which is only influenced by the lowered
u
*
.
