Related Experiment Videos
Energy transfer in Rayleigh-Taylor instability
1Lawrence Livermore National Laboratory, University of California, Livermore, California 94551, USA.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|September 21, 2002
Summary
Direct numerical simulation reveals Rayleigh-Taylor instability dynamics. Energy transfer occurs from large to small scales, with bubble/spike fronts showing positive energy transfer, advancing mixing transition understanding.
Area of Science:
- Fluid dynamics
- Plasma physics
- Turbulence research
Background:
- Rayleigh-Taylor instability is crucial in various physical phenomena.
- Understanding its spatial structure and energy budget is key to predicting mixing processes.
Purpose of the Study:
- To analyze the spatial structure and energy budget of Rayleigh-Taylor instability.
- To characterize flow anisotropy and progress towards the mixing transition.
- To investigate energy transfer mechanisms within the instability.
Main Methods:
- Direct numerical simulation (DNS) with a 512x512x2040 grid.
- Analysis of outer-scale and Taylor Reynolds numbers.
- Definition and use of a mixing parameter.
- Spectral analysis of kinetic energy equation terms.
Main Results:
- Flow exhibits a rough t(3) power law for the outer-scale Reynolds number, reaching ~5500.
- Anisotropy and mixing transition progress are characterized using Taylor microscales.
- Energy spectrum shows the emergence of an inertial range.
- Production and dissipation spectra separate, with net energy transfer from large to small scales.
- Bubble/spike fronts exhibit positive energy transfer; dilatation term moves energy to low-density regions.
Conclusions:
- The study provides detailed insights into the energy budget and spatial structure of Rayleigh-Taylor instability.
- The defined mixing parameter aids in quantifying entrainment and mixing rates.
- DNS results reveal key energy transfer mechanisms and flow evolution towards the mixing transition.