 |
| Titel |
Gravity current down a steeply inclined slope in a rotating fluid |
| VerfasserIn |
G. I. Shapiro, A. G. Zatsepin |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 15, no. 3 ; Nr. 15, no. 3, S.366-374 |
| Datensatznummer |
250012672
|
| Publikation (Nr.) |
 copernicus.org/angeo-15-366-1997.pdf |
|
|
|
|
|
| Zusammenfassung |
| The sinking of dense water down a steep
continental slope is studied using laboratory experiments, theoretical analysis
and numerical simulation. The experiments were made in a rotating tank
containing a solid cone mounted on the tank floor and originally filled with
water of constant density. A bottom gravity current was produced by injecting
more dense coloured water at the top of the cone. The dense water plume
propagated from the source down the inclined cone wall and formed a bottom front
separating the dense and light fluids. The location of the bottom front was
measured as a function of time for various experimental parameters. In the
majority of runs a stable axisymmetric flow was observed. In certain
experiments, the bottom layer became unstable and was broken into a system of
frontal waves which propagated down the slope. The fluid dynamics theory was
developed for a strongly non-linear gravity current forming a near-bottom
density front. The theory takes into account both bottom and interfacial
friction as well as deviation of pressure from the hydrostatic formula in the
case of noticeable vertical velocities. Analytical and numerical solutions were
found for the initial (t < 1/ƒ), intermediate (t ≈ 1/ƒ), and main (t » 1/ƒ) stages,
where ƒ is the Coriolis parameter. The model results show that
during the initial stage non-linear inertial oscillations are developed. During
the main stage, the gravity current is concentrated in the bottom layer which
has a thickness of the order of the Ekman scale. The numerical solutions are
close to the same analytical one. Stability analysis shows that the instability
threshold depends mainly on the Froude number and does not depend on the Ekman
number. The results of laboratory experiments confirm the similarity properties
of the bottom front propagation and agree well with the theoretical predictions. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|