_
ABC and DEF are tsobors whose values are, respectively, Py ond P, and such |
that P, > Py; AF, BE and CD are verticals, directed toword the center of the earth.
HC represents the circulation around any path, R Is the gas constant for dry ‘alr ond
16.
ty represent the mean temperatures along the verticals AF, BE and CD,
Gent, then, neglecting the effect of the eorth’s rotation:
de
"
a
=
ABEF
d
Po
R(T - Ta) log P;
|
~
=
BCDE
Te inate
ah,
P
(2)
A!
It Is clear thet. 1g > Ty ond Te >Ty
The direction of the acceleration of the cite
culation around these paths is therefore “indicated by the orrows in Figure 1.
In the
absence of wind, complete symmetry will exist, so that after a short time interval, a
field of motion will be set up corresponding to Figure 2, and the heated gases and
environmental air will ascend together os a vortex ring.
Figure 2
“Entrainment” is thus seen fo be, not a disorderly mixing of environmental alr in
the wake of a bubble of heated gas, but rather, part of an ordered motion in which the
goses and the atmosphere form a complete system (see Figure 3).
Theoretically, this
system should extend icterally behind the shock wove to infinite distunces; actually,
Josses of energy restrict its lateral extent, while cooling due to adiabotic expansion ond
rodiation Its vertical extent.
LANL pnoe
Turbulence, also, will in time destroy the symmetry of
weep REE a