INVESTIGADORES
MARINO Beatriz Maria
artículos
Título:
Gravity Currents over Porous Substrates
Autor/es:
THOMAS, LP; MARINO, BM; LINDEN, P.
Revista:
JOURNAL OF FLUID MECHANICS
Editorial:
Cambridge University Press
Referencias:
Año: 1998 vol. 366 p. 239 - 258
ISSN:
0022-1120
Resumen:
Results of laboratory experiments are presented in which a fixed
volume of homogeneous
fluid is suddenly released into another fluid of slightly lower density,
over
a horizontal thin metallic grid placed a given distance above the solid
bottom of
a rectangular-cross-section channel. Dense liquid develops as a gravity
current over
the grid at the same time as it partially flows downwards. The results
show that
the gravity current loses mass at an exponential rate through the porous
substrate
with a time constant [tau]; the front velocity and the head of the current
also decrease
exponentially. The loss of mass dominates the flow and, in contrast to
gravity currents
running over solid bottoms, no self-similar inertial regime seems to be
developed. A
simple model is introduced to explain the scaling law of the loss of mass
and the
evolution of the front position. The flow evolution depends on the characteristic
time
of the initial (slumping) phase and the time constant [tau], related to
the initial conditions
and the permeability of the porous substrate, respectively. Qualitative
comparisons
with other gravity currents with loss of mass, such as particle-driven
gravity currents,
are provided.