Mixing and energy transfer in compressible Rayleigh-Taylor turbulence for initial isothermal stratification

Luo，Tengfei1; Wang，Jianchun1,2,3

2022-10-01

10.1103/PhysRevFluids.7.104608

Physical Review Fluids   Impact Factor & Quartile

2469-990X

The effects of stratification parameter (Sr) and flow compressibility on mixing and energy transfer of three-dimensional compressible Rayleigh-Taylor turbulence are studied numerically for initial isothermal stratification at Sr. ranging from 0.5 to 3.0 and at Atwood number At=0.5. Flow compressibility plays an important role in the generation of large-scale kinetic energy, which mainly comes from the conversion of potential energy for small Sr and conversion of internal energy through pressure-dilatation work for large Sr. The latter leads to that bubble heights increase rapidly and the bubbles are bigger at large Sr. The overall statistics of normalized subgrid-scale (SGS) flux of kinetic energy is nearly independent of Sr. The reverse SGS flux is much weaker than the direct SGS flux at middle scales, and increases significantly with increase of Sr. The net upscale cascade of kinetic energy can be identified at large scales, which is more obvious at larger Sr. The compression motions enhance direct SGS flux and the expansion motions strengthen the reverse SGS flux. The conditional average of SGS flux is nearly proportional to the normalized filtered velocity divergence at Sr≤1.0 and the square of filtered velocity divergence at Sr>2.0 in compression regions. The spatially average values of the large-scale pressure-dilatation are similar for different Sr and different times, and they have relatively large negative values at small scales for large Sr.

SCI

English

First

WOS:000878706800001

2-s2.0-85141631267

Scopus

1.Department of Mechanics and Aerospace Engineering,Southern University of Science and Technology,Shenzhen,518055,China
2.Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou),Guangzhou,511458,China
3.Guangdong-Hong Kong-Macao Joint Laboratory for Data-Driven Fluid Mechanics and Engineering Applications,Southern University of Science and Technology,Shenzhen,518055,China

Luo，Tengfei,Wang，Jianchun. Mixing and energy transfer in compressible Rayleigh-Taylor turbulence for initial isothermal stratification[J]. Physical Review Fluids,2022,7(10).

Luo，Tengfei,&Wang，Jianchun.(2022).Mixing and energy transfer in compressible Rayleigh-Taylor turbulence for initial isothermal stratification.Physical Review Fluids,7(10).

Luo，Tengfei,et al."Mixing and energy transfer in compressible Rayleigh-Taylor turbulence for initial isothermal stratification".Physical Review Fluids 7.10(2022).