Spanwise homogeneous buoyancy-drag model for Rayleigh-Taylor mixing and experimental evaluation

Journal Article · Thu Jun 01 04:00:00 EDT 2000 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.874060· OSTI ID:20216534

Dimonte, Guy ^[1]

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1. Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

A buoyancy-drag model for Rayleigh-Taylor (RT) mixing is developed on the premise that the bubble and spike regions behave as distinct and spanwise homogeneous fluids. Then, mass conservation is applied accross the mixing zone to obtain their average mixture densities dynamically. These are used to explicitly calculate the inertia and buoyancy terms in the evolutionary equation. The only unknown parameter in the model is the Newtonian drag constant C{approx}2.5{+-}0.6, which is determined from turbulent RT experiments over various Atwood numbers A and acceleration histories g(t). The bubble (i=2) and spike (i=1) amplitudes are found to obey the familiar h{sub i}={alpha}{sub i}Agt{sup 2} for a constant g and h{sub i}{approx}t{sup {theta}{sub i}} for an impulsive g. For bubbles, both {alpha}{sub 2} and {theta}{sub 2} are insensitive to A. For the spikes, both {alpha}{sub 1} and {theta}{sub 1} increase as a power law with the density ratio. However, {theta}{sub 1} is not universal because it depends on the initial value of h{sub 1}/h{sub 2}. (c) 2000 American Institute of Physics.

• OSTI ID: 20216534
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 6 Vol. 7; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BUBBLES
DRAG
EXPERIMENTAL DATA
MIXING
PLASMA FLUID EQUATIONS
PLASMA INSTABILITY
RAYLEIGH-TAYLOR INSTABILITY
THEORETICAL DATA
TURBULENCE