127 citations · 775 across the 18 of their papers we have counts for
18 papers
Mixed baroclinic convection in a cavity
Abhishek Kumar, Alban Pothérat
We study the convective patterns that arise in a nearly semi-cylindrical cavity fed in with hot fluid at the upper boundary, bounded by a cold, porous semi-circular boundary at the…
Turbulence in a stably stratified fluid: Onset of global anisotropy as a function of the Richardson number
Jayanta K. Bhattacharjee, Abhishek Kumar, Mahendra K. Verma
It is necessary to introduce an external forcing to induce turbulence in a stably stratified fluid. The Heisenberg eddy viscosity technique should in this case suffice to calculate…
Sweeping effect and Taylor's hypothesis via correlation function
Mahendra Kumar Verma, Abhishek Kumar, Akanksha Gupta
We demonstrate the sweeping effect in turbulence using numerical simulations of hydrodynamic turbulence without a mean velocity. The velocity correlation function, C(k, τ ) decays…
Stochastic bistable systems, and competing hysteresis and phase coexistence
Mahendra K. Verma, Abhishek Kumar, Adhip Pattanayak
In this paper we describe the solution of a stochastic bistable system from a dynamical perspective. We show how a single framework with variable noise can explain hysteresis at ze…
Scaling of a Fast Fourier Transform and a Pseudo-spectral Fluid Solver up to 196608 cores
Anando G. Chatterjee, Mahendra K. Verma, Abhishek Kumar +3
In this paper we present scaling results of a FFT library, FFTK, and a pseudospectral code, Tarang, on grid resolutions up to grid using 65536 cores of Blue Gene/P and 196…
Transient flows and reorientations of large-scale convection in a cubic cell
Andrei Vasiliev, Peter Frick, Abhishek Kumar +3
The transient processes of a turbulent large-scale convective circulation (LSC) in a cubic cell are investigated using large-eddy simulations for Rayleigh number $\Ray=10^8$ and Pr…
Statistical features of rapidly rotating decaying turbulence: enstrophy and energy spectra, and coherent structures
Manohar K. Sharma, Abhishek Kumar, Mahendra K. Verma +1
In this paper we investigate the properties of rapidly rotating decaying turbulence using numerical simulations and phenomenological modelling. We find that as the turbulent flow e…
Complexity of viscous dissipation in turbulent thermal convection
Shashwat Bhattacharya, Ambrish Pandey, Abhishek Kumar +1
Using direct numerical simulations of turbulent thermal convection for Rayleigh number () between and and unit Prandtl number, we derive scaling relation…
Large eddy simulations using renormalized viscosity
Sumit Vashishtha, Anando Chatterjee, Abhishek Kumar +1
In this paper, we have used renormalized viscosity for performing large eddy simulations (LES) of decaying homogeneous and isotropic turbulence inside a periodic cube on coarse gri…
Energy Spectra and Fluxes in Dissipation Range of Turbulent and Laminar Flows
Mahendra K. Verma, Abhishek Kumar, Praveen Kumar +4
Two well-known turbulence models that describe the energy spectrum in the inertial and dissipative ranges simultaneously are by Pao~(1965) and Pope~(2000). In this paper, we comput…
Surface Ocean Enstrophy, Kinetic Energy Fluxes and Spectra from Satellite Altimetry
Hemant Khatri, Jai Sukhatme, Abhishek Kumar +1
Enstrophy, kinetic energy (KE) fluxes and spectra are estimated in different parts of the mid-latitudinal oceans via altimetry data. To begin with, using geostrophic currents deriv…
Phenomenology of buoyancy-driven turbulence: recent results
Mahendra K. Verma, Abhishek Kumar, Ambrish Pandey
In this paper, we review the recent developments in the field of buoyancy-driven turbulence. Scaling and numerical arguments show that the stably-stratified turbulence with moderat…
Phenomenology of two-dimensional stably stratified turbulence under large-scale forcing
Abhishek Kumar, Mahendra K. Verma, Jai Sukhatmae
In this paper we characterize the scaling of energy spectra, and the interscale transfer of energy and enstrophy, for strongly, moderately and weakly stably stratified two-dimensio…
Near isotropic behaviour of turbulent thermal convection
Dinesh Nath, Ambrish Pandey, Abhishek Kumar +1
We investigate the anisotropy in turbulent convection in a 3D box using direct numerical simulation. We compute the anisotropic parameter , wh…
Applicability of Taylor's hypothesis in thermally driven turbulence
Abhishek Kumar, Mahendra K. Verma
In this paper, we show that in the presence of large-scale circulation (LSC), Taylor's hypothesis can be invoked to deduce the energy spectrum in thermal convection using real spac…
Energy Spectrum of Buoyancy-Driven Turbulence
Abhishek Kumar, Anando G. Chatterjee, Mahendra K. Verma
Using high-resolution direct numerical simulation and arguments based on the kinetic energy flux , we demonstrate that for stably stratified flows, the kinetic energy spectrum…
A Shell Model for Buoyancy-Driven Turbulence
Abhishek Kumar, Mahendra K. Verma
In this paper we present a unified shell model for stably stratified and convective turbulence. Numerical simulation of this model for stably stratified flow shows Bolgiano-Obukhbo…
Energy spectrum of Buoyancy-driven Flows
Abhishek Kumar, Anando G. Chatterjee, Mahendra K. Verma
Using high-resolution direct numerical simulation and arguments based on the kinetic energy flux , we demonstrate that for stably stratified flows, the kinetic energy spectrum…