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Your search keyword '"John, John Panickacheril"' showing total 2 results
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1. Strongly superadiabatic and stratified limits of compressible convection

Author

John, John Panickacheril and Schumacher, Jörg

Subjects
Fluid Dynamics (physics.flu-dyn), FOS: Physical sciences, Physics - Fluid Dynamics
Abstract

Fully compressible turbulent convection is studied in three-dimensional numerical simulations. Superadiabaticity and dissipation number, which measures the strength of stratification of adiabatic equilibria, cause two limits -- nearly top-down-symmetric, strongly superadiabatic and highly top-down-asymmetric, strongly stratified convection. Highest turbulent Mach numbers $M_t$ follow for a symmetric blend of both limits, the fully compressible case. We show that buoyancy-driven convection gives always $M_t < 1$. Strongly stratified convection leads to a fluctuation-reduced top layer, reduced global heat transfer, and differing asymmetric boundary layer dynamics at the top and bottom.

Published
2023

2. Solenoidal Scaling Laws for Compressible Mixing.

Author

John, John Panickacheril, Donzis, Diego A., and Sreenivasan, Katepalli R.

Subjects
*MIXING, *REYNOLDS number, *TURBULENCE, *COMPUTER simulation
Abstract

Mixing of passive scalars in compressible turbulence does not obey the same classical Reynolds number scaling as its incompressible counterpart. We first show from a large database of direct numerical simulations that even the solenoidal part of the velocity field fails to follow the classical incompressible scaling when the forcing includes a substantial dilatational component. Though the dilatational effects on the flow remain significant, our main results are that both the solenoidal energy spectrum and the passive scalar spectrum assume incompressible forms, and that the scalar gradient essentially aligns with the most compressive eigenvalue of the solenoidal part, provided that only the solenoidal components are consistently used for scaling. A slight refinement of this statement is also pointed out. [ABSTRACT FROM AUTHOR]

Published
2019
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