The Benilov and Ly (2002) model accounts for the transfer of kinetic
energy from breaking waves to turbulence and the length scale is not
constrained by formula (3.33). This model is therefore expected to perform
well in the wave-stirred layer. Note that in the diffusive and logarithmic
sublayers this model is practically identical to CB94.
An important feature of the Benilov and Ly (2002) model is that it does not
require the z 0 to be specified (as in CB94 model). The surface roughness
from waterside is no longer a model parameter in Benilov and Ly (2002). In
the wave-stirred layer, the Benilov and Ly (2002) model, nevertheless,
employs a simplified version of the dissipation rate budget equation, which
unfortunately introduces a new adjustable parameter, which is the effective
depth of the wave-stirred layer, H w-s /H s .
Figure 3-19 summarizes the results of the recent field and theoretical
studies of wave-enhanced turbulence. In order to minimize the influence of
thermohaline stratification effects on near-surface turbulence characteristics,
only the data obtained during high wind speeds are analyzed. The one-month
long data set of Soloviev and Lukas (2003) was collected under various
wind-wave conditions. The contribution of remotely forced swell to the
significant wave height, H s , could contribute some scatter in the
nondimensional dissipation rate, HH s /F 0 , and the nondimensional depth,
|z|/H s .
Solution (3.80) is shown in Figure 3-19 in comparison with the field
data. At H w-s /H s = 0.4, parameterization formula (3.80) approximates
reasonably well both Thorpe et al. (2003a) and Drennan et al (1996) data
sets (in contrast to the analysis shown in Figure 3-13b); it is also
sistent with the Soloviev and Lukas (1993) data.
3.3.4 Concluding remarks on wave-enhanced turbulence
One of the first observations of near-surface turbulence dissipation was
made by Stewart and Grant (1962) with a velocity sensor (thermoanemometer) mounted on the bow of a vessel. Their data indicated that
wave-generated turbulence essentially dissipates above the trough line.
A similar conclusion was reached by Soloviev et al. (1988) based on the
analysis of dissipation rate profiles obtained with a free-rising profiler and of
the observations made by Arsenyev et al. (1975), Jones and Kenney (1977),
Dillon et al. (1981), and Oakey and Elliott (1982). In nondimensional
coordinates
2
/
g z u and
3
/
z u
HN
, the dissipation rates were near or slightly
exceeding (within a factor of 2-3) the logarithmic layer prediction. Soloviev
et al. (1988) suggested that all of these data came mainly from below the
layer of wave-enhanced turbulence. However, these analyzed data were
confined to moderate and low wind speed conditions. Later, Greenan et al.
(2001) and Thorpe et al. (2003a) obtained dissipation rate data sets under
Chapter 3: NEAR-SURFACE TURBULENCE
195
con-
energy from breaking waves to turbulence and the length scale is not
constrained by formula (3.33). This model is therefore expected to perform
well in the wave-stirred layer. Note that in the diffusive and logarithmic
sublayers this model is practically identical to CB94.
An important feature of the Benilov and Ly (2002) model is that it does not
require the z 0 to be specified (as in CB94 model). The surface roughness
from waterside is no longer a model parameter in Benilov and Ly (2002). In
the wave-stirred layer, the Benilov and Ly (2002) model, nevertheless,
employs a simplified version of the dissipation rate budget equation, which
unfortunately introduces a new adjustable parameter, which is the effective
depth of the wave-stirred layer, H w-s /H s .
Figure 3-19 summarizes the results of the recent field and theoretical
studies of wave-enhanced turbulence. In order to minimize the influence of
thermohaline stratification effects on near-surface turbulence characteristics,
only the data obtained during high wind speeds are analyzed. The one-month
long data set of Soloviev and Lukas (2003) was collected under various
wind-wave conditions. The contribution of remotely forced swell to the
significant wave height, H s , could contribute some scatter in the
nondimensional dissipation rate, HH s /F 0 , and the nondimensional depth,
|z|/H s .
Solution (3.80) is shown in Figure 3-19 in comparison with the field
data. At H w-s /H s = 0.4, parameterization formula (3.80) approximates
reasonably well both Thorpe et al. (2003a) and Drennan et al (1996) data
sets (in contrast to the analysis shown in Figure 3-13b); it is also
sistent with the Soloviev and Lukas (1993) data.
3.3.4 Concluding remarks on wave-enhanced turbulence
One of the first observations of near-surface turbulence dissipation was
made by Stewart and Grant (1962) with a velocity sensor (thermoanemometer) mounted on the bow of a vessel. Their data indicated that
wave-generated turbulence essentially dissipates above the trough line.
A similar conclusion was reached by Soloviev et al. (1988) based on the
analysis of dissipation rate profiles obtained with a free-rising profiler and of
the observations made by Arsenyev et al. (1975), Jones and Kenney (1977),
Dillon et al. (1981), and Oakey and Elliott (1982). In nondimensional
coordinates
2
/
g z u and
3
/
z u
HN
, the dissipation rates were near or slightly
exceeding (within a factor of 2-3) the logarithmic layer prediction. Soloviev
et al. (1988) suggested that all of these data came mainly from below the
layer of wave-enhanced turbulence. However, these analyzed data were
confined to moderate and low wind speed conditions. Later, Greenan et al.
(2001) and Thorpe et al. (2003a) obtained dissipation rate data sets under
Chapter 3: NEAR-SURFACE TURBULENCE
195
con-