Volvocida
340
(2) mountain built up by the materials ejected from the interior of the earth
through a vent. ~volcanism.
Volvocida order of the class Chlorophyceae (phylum Chlorophyta), of mainly freshwater species. Formerly regarded as an order of the subphylum Mastigophora
(phylum Sarcomastigophora, ~Protozoa). The cells have a cellulose wall and
can be nonmotile or motile (e.g., Chlamydomonas) and colony forming (e.g.,
Volvox).
vortex the rotating motion of a large number of material particles around a
common center. A line at every point parallel to the local vorticity vector (the
axis of rotation) is called a vortex line in hydrodynamics. The vortex lines
drawn through a closed contour form a vortex tube, and the fluid that is contained within this tube is a vortex filament, or briefly, a vortex. In hydrodynamics, vortices are convenient in describing the changes in vorticity.
vorticity of a fluid element is a measure of the spin of that element, proportional to its angular momentum. Positive vorticity means a clockwise rotation,
negative an anticlockwise rotation. In vector analysis vorticity is defined as
the curl of the velocity. On the rotating earth absolute vorticity is the sum of
the vorticity relative to the earth (relative vorticity) and the rotation of the
earth (planetary vorticity). Potential vorticity is a quantity that in homogeneous water is equal to absolute vorticity, divided by depth. In stratified
water it depends on the stratification. This potential vorticity is a conservative quantity, and is sometimes used as a dynamic tracer.
Viiisiilii frequency ~Brunt-Vaisala frequency.
340
(2) mountain built up by the materials ejected from the interior of the earth
through a vent. ~volcanism.
Volvocida order of the class Chlorophyceae (phylum Chlorophyta), of mainly freshwater species. Formerly regarded as an order of the subphylum Mastigophora
(phylum Sarcomastigophora, ~Protozoa). The cells have a cellulose wall and
can be nonmotile or motile (e.g., Chlamydomonas) and colony forming (e.g.,
Volvox).
vortex the rotating motion of a large number of material particles around a
common center. A line at every point parallel to the local vorticity vector (the
axis of rotation) is called a vortex line in hydrodynamics. The vortex lines
drawn through a closed contour form a vortex tube, and the fluid that is contained within this tube is a vortex filament, or briefly, a vortex. In hydrodynamics, vortices are convenient in describing the changes in vorticity.
vorticity of a fluid element is a measure of the spin of that element, proportional to its angular momentum. Positive vorticity means a clockwise rotation,
negative an anticlockwise rotation. In vector analysis vorticity is defined as
the curl of the velocity. On the rotating earth absolute vorticity is the sum of
the vorticity relative to the earth (relative vorticity) and the rotation of the
earth (planetary vorticity). Potential vorticity is a quantity that in homogeneous water is equal to absolute vorticity, divided by depth. In stratified
water it depends on the stratification. This potential vorticity is a conservative quantity, and is sometimes used as a dynamic tracer.
Viiisiilii frequency ~Brunt-Vaisala frequency.