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Your search keyword '"Mitra, Dhrubaditya"' showing total 182 results
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182 results on '"Mitra, Dhrubaditya"'

178. Dynamics of saturated energy condensation in two-dimensional turbulence.

Author

Chi-kwan Chan, Mitra, Dhrubaditya, and Brandenburg, Axel

Subjects
*CONDENSATION, *DIMENSIONAL analysis, *TURBULENCE, *BOSE-Einstein condensation, *NAVIER-Stokes equations, *COHERENCE (Physics), *VISCOSITY, *CASCADES (Fluid dynamics)
Abstract

In two-dimensional forced Navier-Stokes turbulence, energy cascades to the largest scales in the system to form a pair of coherent vortices known as the Bose condensate. We show, both numerically and analytically, that the energy condensation saturates and the system reaches a statistically stationary state. The time scale of saturation is inversely proportional to the viscosity and the saturation energy level is determined by both the viscosity and the force. We further show that, without sufficient resolution to resolve the small-scale enstrophy spectrum, numerical simulations can give a spurious result for the saturation energy level. We also find that the movement of the condensate is similar to the motion of an inertial particle with an effective drag force. Furthermore, we show that the profile of the saturated coherent vortices can be described by a Gaussian core with exponential wings. [ABSTRACT FROM AUTHOR]

Published
2012
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179. Comparative phytotoxicity of nitrophenolic soil pollutants and their microbial metabolites to the growth of cucumber

Author

Mitra, Dhrubaditya and Vaidyanathan, CS

Subjects
Biochemistry
Abstract

2,4-Dinitrophenol and paranitrophenol are two major soil pollutants which are known to be metabolized by different soil microbes. Relative phytotoxicities of these parent compounds and their metabolic transformation products to the growth of cucumber seedlings were assessed. It was evident that such microbial transformations widely occurring in the soil are effective detoxification reactions and are beneficial for the plants.

Published
1982

182. Rate of formation of caustics in heavy particles advected by turbulence.

Author

Bhatnagar A, Pandey V, Perlekar P, and Mitra D

Abstract

The rate of collision and the relative velocities of the colliding particles in turbulent flows are a crucial part of several natural phenomena, e.g. rain formation in warm clouds and planetesimal formation in protoplanetary discs. The particles are often modelled as passive, but heavy and inertial. Within this model, large relative velocities emerge due to formation of singularities (caustics) of the gradient matrix of the velocities of the particles. Using extensive direct numerical simulations of heavy particles in both two (direct and inverse cascade) and three-dimensional turbulent flows, we calculate the rate of formation of caustics, [Formula: see text] as a function of the Stokes number ([Formula: see text]). The best approximation to our data is [Formula: see text], in the limit [Formula: see text] where [Formula: see text] is a non-universal constant. This article is part of the theme issue 'Scaling the turbulence edifice (part 2)'.

Published
2022
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