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Seminar: Fluid Mechanics

Decoding Physics of Convective Turbulence

Speaker: Mahendra Verma
Organization: Indian Institute of Technology Kanpur
Time: 2017-08-28 10:00
Place: Teknikringen 8

Abstract

In this talk we present the present status of the turbulence phenomenology for turbulent thermal convection. Using pseudospectral simulations of turbulent thermal convection at very high resolution (4096^3) and high Rayleigh number (1.1 × 10^11) with unit Prandtl number, we conclude that convective turbulence exhibits behaviour similar to fluid turbulence, that is, Kolmogorov’s k^?5/3 spectrum with forward and local energy transfers, along with a nearly isotropic energy distribution. The energy transfer diagnostics have provided a very useful diagnostics to this question. We also compute the rms values of various terms of the momentum equation of turbulent convection. We show that the acceleration of a fluid parcel is provided mainly by the pressure gradient, and the buoyancy and dissipation term are quite close to each other. Thus, the effect of buoyancy is annulled in convective turbulence, leading to Kolmogorov’s theory of turbulence.