Interaction of a negatively buoyant line plume with a density interface

C. Y. Ching, H. J.S. Fernando, Yign Noh

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Laboratory experiments were carried out to investigate the interaction between turbulent line buoyant plumes and sharp density interfaces, with the aim of using the results to interpret oceanic observations pertinent to crack openings in the polar ice-cap (leads). These openings take the form of long narrow channels, and are often modeled as line bouyant plumes. The plumes descend as in a homogenoous fluid, impinge on the density interface, and then spread horizontally as gravity currents. Depending on the Richardson number Ri = Δ bld/q0 2 3, where Δb is the buoyancy jump across the interface, lD is the half-width of the plume before the impingement and q0is the buoyancy flux per unit length of the source, different flow patterns were identified. When Ri < 0.5, the plumes penetrate deep into the bottom layer, deflect horizontally and then spread while showing little vertical rise. When 0.6 < Ri < 5, the penetration is significant, but the fluid bounces back after entraining heavy fluid from the lower layer and then spreads horizontally above the interface as a gravity current. Appreciable mixing between this current and the lower layer was detected when Ri <1. When Ri > 10, the penetration was small and a sharp-nosed gravity current emerged some time after the impact. Measurements were made on the penetration depth, the velocities of the gravity current and the subsurface flow towards the plume, the entrainment rate and other wave parameters. Possible implications of the results for oceanic cases are also discussed.

Original languageEnglish
Pages (from-to)367-388
Number of pages22
JournalDynamics of Atmospheres and Oceans
Volume19
Issue number1-4
DOIs
Publication statusPublished - 1993 Oct 29

Fingerprint

Gravitation
plume
Buoyancy
gravity
buoyancy
penetration
Flow patterns
Ice
Richardson number
Fluxes
Cracks
ice cap
subsurface flow
Fluids
flow pattern
entrainment
crack
Experiments
fluid

All Science Journal Classification (ASJC) codes

  • Oceanography
  • Geology
  • Computers in Earth Sciences
  • Atmospheric Science

Cite this

Ching, C. Y. ; Fernando, H. J.S. ; Noh, Yign. / Interaction of a negatively buoyant line plume with a density interface. In: Dynamics of Atmospheres and Oceans. 1993 ; Vol. 19, No. 1-4. pp. 367-388.
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Interaction of a negatively buoyant line plume with a density interface. / Ching, C. Y.; Fernando, H. J.S.; Noh, Yign.

In: Dynamics of Atmospheres and Oceans, Vol. 19, No. 1-4, 29.10.1993, p. 367-388.

Research output: Contribution to journalArticle

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