354
CAW. H. tiIBSON ET Al..
I’ARI.E 1. Viscous and thermal dissipation rates in laboratory. atmospheric, and
oceanic turbulence experiments”
Atrnosphcric
Water tunnel’
Air jet.
boundary layer‘
Ocean‘.’.*,’
F (cm2,sec3)
lo-IOJ
104
10’
10‘’ 10
y ( C2:sec)
10-’-10-6
10- ’
10-2-10-4
10
‘‘k = ?~(ef,); eij = f ( ~ , . ~
+ uj,,); x = 2D(7/); where u = velocity.
T :
= remperature. Y = kinematic viscosity, and D = rhrrmnl iliffusivity.
‘ Gibson cf a/. (1968).
‘’ Frkhe tv al. (1972).
‘Grant cf [ I / . (1962).
f Nasmyth (lY70).
Williams and Gibson (1973).
Hacker (1973).
Gibson ef d. (19704
probes have been available for several years now and were used in the
present study. They are not without difficulty, however. A recent laboratory
and field evaluation (Frey and McNally, 1973) of such probes for oceanographic flow sensors concludes with the sentence, ” Finally, caveat emptor.” The
situation is like comparing democracy to other forms of government; hot
film probes are the worst possible sensors for oceanic turbulence,.except for
all others that have been tried.’
The earliest turbulence and temperature measurements in the ocean were
carried out by a Canadian group working in a tidal channel (Grant er al.,
1962) and open ocean (Stewart and Grant, 1962; Grant er al., 1968a,b;
Nasmyth, 1970) with film and thermistor sensors towed by a ship and
mounted on a submarine. Values of E and x as small as
cm2/sec3 and
10- ’ “C2/sec were reported.
Kolesnikov (1960) describes a “turbulimeter” developed in 1955 which
was apparently used for millimeter scale measurements of turbulence and
temperature fluctuations in the ocean and under ice. Few details are given of
the method of measurement or results. Ozmidov and his group (Ozmidov
and Belyaev, 1972; see also Ozmidov, 1971) have towed hot film
anemometer and conductivity probes to measure small scale turbulence and
temperature fluctuations in the Atlantic and Indian Oceans on a number of
cruises since 1969. Few details are given of the instrumentation or results,
except that generally turbulence was found to exist only on scales less than a
meter and with marginal shear Reynolds number.
In the present paper some results are presented from experiments with
instruments towed in the Cromwell current at about 100m depth, suI The hydroresistance anemometer probe recently developed by the Russians may prove to
be the exception (Vorobjev et a/., 1974).
CAW. H. tiIBSON ET Al..
I’ARI.E 1. Viscous and thermal dissipation rates in laboratory. atmospheric, and
oceanic turbulence experiments”
Atrnosphcric
Water tunnel’
Air jet.
boundary layer‘
Ocean‘.’.*,’
F (cm2,sec3)
lo-IOJ
104
10’
10‘’ 10
y ( C2:sec)
10-’-10-6
10- ’
10-2-10-4
10
‘‘k = ?~(ef,); eij = f ( ~ , . ~
+ uj,,); x = 2D(7/); where u = velocity.
T :
= remperature. Y = kinematic viscosity, and D = rhrrmnl iliffusivity.
‘ Gibson cf a/. (1968).
‘’ Frkhe tv al. (1972).
‘Grant cf [ I / . (1962).
f Nasmyth (lY70).
Williams and Gibson (1973).
Hacker (1973).
Gibson ef d. (19704
probes have been available for several years now and were used in the
present study. They are not without difficulty, however. A recent laboratory
and field evaluation (Frey and McNally, 1973) of such probes for oceanographic flow sensors concludes with the sentence, ” Finally, caveat emptor.” The
situation is like comparing democracy to other forms of government; hot
film probes are the worst possible sensors for oceanic turbulence,.except for
all others that have been tried.’
The earliest turbulence and temperature measurements in the ocean were
carried out by a Canadian group working in a tidal channel (Grant er al.,
1962) and open ocean (Stewart and Grant, 1962; Grant er al., 1968a,b;
Nasmyth, 1970) with film and thermistor sensors towed by a ship and
mounted on a submarine. Values of E and x as small as
cm2/sec3 and
10- ’ “C2/sec were reported.
Kolesnikov (1960) describes a “turbulimeter” developed in 1955 which
was apparently used for millimeter scale measurements of turbulence and
temperature fluctuations in the ocean and under ice. Few details are given of
the method of measurement or results. Ozmidov and his group (Ozmidov
and Belyaev, 1972; see also Ozmidov, 1971) have towed hot film
anemometer and conductivity probes to measure small scale turbulence and
temperature fluctuations in the Atlantic and Indian Oceans on a number of
cruises since 1969. Few details are given of the instrumentation or results,
except that generally turbulence was found to exist only on scales less than a
meter and with marginal shear Reynolds number.
In the present paper some results are presented from experiments with
instruments towed in the Cromwell current at about 100m depth, suI The hydroresistance anemometer probe recently developed by the Russians may prove to
be the exception (Vorobjev et a/., 1974).