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fulvie acids
speed and friction is assumed (Rayleigh friction). In the interior of a fluid,
friction also may occur as the result of current shear. The transport of
momentum from one layer to the other by turbulence depends on the shear
and the strength of the turbulence, expressed by the eddy viscosity.
fringing reef -treef.
front a front or a frontal zone is a sloping interface between two water bodies
with different properties. Fronts may persist for some time when the advection at either side of the front counteracts cross-frontal mixing. This means
that across a front the current component at right angles will change rapidly. There are different types of fronts. The larger oceanic frontal zones are
the result of large-scale advection of different water masses, e.g., between
the subtropical and the subpolar gyre. Coastal fronts develop when water of
estuarine origin flows into the open sea. Thermal fronts may develop in
shallow water between vertically well-mixed water and stratified water further offshore. The converging water at the surface is effective in concentrating foam or flotsam at the surface along the front. Concentration of particulate matter along a front may also increase biological activity.
Froude number a non dimensional number occurring in similarity theory and used
in model experiments in open channels, where the hydrostatic pressure
plays a role. The Froude number (named after the British engineer W. Froude,
who introduced scale experiments in ship building in 1871), Fr, gives the
ratio between the current speed u and the speed of ~(oP)gation of a long
wave, c, in water of a depth D, and equals Fr = ul c = ul gD. It also gives a
criterion between two possible types of flow, subcritical (the normal condition in oceanography) and supercritical flow, with Fr respectively smaller
and larger than 1. A tidal bore is an example of the transition between the
two types of flow. The Froude number is equal to the inverse square root of
the bulk Richardson number, applied to the total layer of water.
frozen-field hypothesis hypothesis in turbulence studies, implying that the time variations of the turbulent field at a given point are similar to the spatial variations
at each moment. So similar time variations would be found if the turbulent field
were suddenly "frozen" and moved along this point with the mean velocity.
frustule -tBaciliariophyta.
fueoxanthin -tcarotenoids.
fulvie acids these ill-defined naturally occurring acids are part of organic matter (humus) (fulvus=yellow). The compounds contain hydrocarbons (n-alkanes) with a carbon range of C 14 to C 3 1' which is also characteristic of fatty acids
fulvie acids
speed and friction is assumed (Rayleigh friction). In the interior of a fluid,
friction also may occur as the result of current shear. The transport of
momentum from one layer to the other by turbulence depends on the shear
and the strength of the turbulence, expressed by the eddy viscosity.
fringing reef -treef.
front a front or a frontal zone is a sloping interface between two water bodies
with different properties. Fronts may persist for some time when the advection at either side of the front counteracts cross-frontal mixing. This means
that across a front the current component at right angles will change rapidly. There are different types of fronts. The larger oceanic frontal zones are
the result of large-scale advection of different water masses, e.g., between
the subtropical and the subpolar gyre. Coastal fronts develop when water of
estuarine origin flows into the open sea. Thermal fronts may develop in
shallow water between vertically well-mixed water and stratified water further offshore. The converging water at the surface is effective in concentrating foam or flotsam at the surface along the front. Concentration of particulate matter along a front may also increase biological activity.
Froude number a non dimensional number occurring in similarity theory and used
in model experiments in open channels, where the hydrostatic pressure
plays a role. The Froude number (named after the British engineer W. Froude,
who introduced scale experiments in ship building in 1871), Fr, gives the
ratio between the current speed u and the speed of ~(oP)gation of a long
wave, c, in water of a depth D, and equals Fr = ul c = ul gD. It also gives a
criterion between two possible types of flow, subcritical (the normal condition in oceanography) and supercritical flow, with Fr respectively smaller
and larger than 1. A tidal bore is an example of the transition between the
two types of flow. The Froude number is equal to the inverse square root of
the bulk Richardson number, applied to the total layer of water.
frozen-field hypothesis hypothesis in turbulence studies, implying that the time variations of the turbulent field at a given point are similar to the spatial variations
at each moment. So similar time variations would be found if the turbulent field
were suddenly "frozen" and moved along this point with the mean velocity.
frustule -tBaciliariophyta.
fueoxanthin -tcarotenoids.
fulvie acids these ill-defined naturally occurring acids are part of organic matter (humus) (fulvus=yellow). The compounds contain hydrocarbons (n-alkanes) with a carbon range of C 14 to C 3 1' which is also characteristic of fatty acids