124 citations · 1.5k across the 64 of their papers we have counts for
65 papers
Traveling waves, phase separation and pattern formation in the active stepping stone model
Rashmiranjan Bhutia, Prasad Perlekar, Kabir Ramola
Selective advantage leads to the proliferation of a species into an ecosystem. On the other hand, self-propulsion can lead to dynamic clustering of individuals. To analyze the intr…
Gappy Reconstruction of Bubbly Flows by Guided Diffusion Models
Hridey Narula, Tianyi Li, Michele Buzzicotti +2
Experiments in multiphase flows are often limited in their ability to simultaneously obtain velocity measurements in different phases. At the same time, flow reconstruction from ph…
Flocking and mesoscale turbulence in three-dimensional active fluids
Prasad Perlekar
We numerically study the three-dimensional turbulence in a minimal model of an active fluid--the Toner-Tu-Swift-Hohenburg equation. For small activity, we observe bacterial turbule…
Bridging Filtering and Point-Splitting Approaches for Variable-Density Flows
Hridey Narula, Prasad Perlekar
Energy transfer in turbulent flows is typically described either through correlation functions, via the Kármán-Howarth-Monin relation, or through a scale-by-scale budget of the fil…
Instabilities and turbulence in extensile swimmer suspensions
Purnima Jain, Navdeep Rana, Roberto Benzi +1
We study low Reynolds number turbulence in a suspension of polar, extensile, self-propelled inertial swimmers. We review the bend and splay mechanisms that destabilize an ordered f…
Scale-by-scale energy transfers in bubbly flows
Hridey Narula, Vikash Pandey, Dhrubaditya Mitra +1
Buoyancy-driven bubbly flows naturally have spatially-dependent density fields, which allow for multiple definitions of the scale-dependent (or filtered) energy. A priori, it is no…
Diffusive noise controls early stages of genetic demixing
Rashmiranjan Bhutia, Stephy Jose, Prasad Perlekar +1
Theoretical descriptions of the stepping-stone model, a cornerstone of spatial population genetics, have long overlooked diffusive noise arising from migration dynamics. We derive…
Emergent asymmetry in confined bioconvection
Martin A. Bees, Prasad Perlekar
Bioconvection is the prototypical active matter system for hydrodynamic instabilities and pattern formation in suspensions of biased swimming microorganisms, particularly at the di…
Inertia drives concentration-wave turbulence in swimmer suspensions
Purnima Jain, Navdeep Rana, Sriram Ramaswamy +1
We discover an instability mechanism in suspensions of self-propelled particles that does not involve active stress. Instead, it is driven by a subtle interplay of inertia, swimmer…
Intermittency in the not-so-smooth elastic turbulence
Rahul K. Singh, Prasad Perlekar, Dhrubaditya Mitra +1
Elastic turbulence is the chaotic fluid motion resulting from elastic instabilities due to the addition of polymers in small concentrations at very small Reynolds ($\mbox{Re}$) num…
Defect turbulence in a dense suspension of polar, active swimmers
Navdeep Rana, Rayan Chatterjee, Sunghan Ro +3
We study the effects of inertia in dense suspensions of polar swimmers. The hydrodynamic velocity field and the polar order parameter field describe the dynamics of the suspension.…
Energy spectra of buoyancy-driven bubbly flow in a vertical Hele-Shaw cell
Rashmi Ramadugu, Vikash Pandey, Prasad Perlekar
We present direct numerical simulations (DNS) study of confined buoyancy-driven bubbly flows in a Hele-Shaw setup. We investigate the spectral properties of the flow and make compa…
Kolmogorov Turbulence Coexists with Pseudo-Turbulence in Buoyancy-Driven Bubbly Flows
Vikash Pandey, Dhrubaditya Mitra, Prasad Perlekar
We investigate spectral properties of buoyancy driven bubbly flows. Using high-resolution numerical simulations and phenomenology of homogeneous turbulence, we identify the relevan…
Large is different: non-monotonic behaviour of elastic range scaling in polymeric turbulence at large Reynolds and Deborah numbers
Marco E Rosti, Prasad Perlekar, Dhrubaditya Mitra
We use direct numerical simulations to study homogeneous, and isotropic turbulent flows of dilute polymer solutions at high Reynolds and Deborah numbers. We find that for small wav…
Rate of formation of caustics in heavy particles advected by turbulence
Akshay Bhatnagar, Vikash Pandey, Prasad Perlekar +1
The rate of collision and the relative velocities of the colliding particles in turbulent flows is a crucial part of several natural phenomena, e.g., rain formation in warm clouds…
Coagulation drives turbulence in binary fluid mixtures
Akshay Bhatnagar, Prasad Perlekar, Dhrubaditya Mitra
We use direct numerical simulations and scaling arguments to study coarsening in binary fluid mixtures with a conserved order parameter in the droplet-spinodal regime -- the volume…
Phase ordering, topological defects, and turbulence in the 3D incompressible Toner-Tu equation
Navdeep Rana, Prasad Perlekar
We investigate phase ordering dynamics of the incompressible Toner-Tu equation in three dimensions. We show that the phase ordering proceeds via defect merger events and the dynami…
Turbulence modulation in buoyancy-driven bubbly flows
Vikash Pandey, Dhrubaditya Mitra, Prasad Perlekar
We present a Direct Numerical Simulation (DNS) study of buoyancy-driven bubbly flows in the presence of large scale driving that generates turbulence. On increasing the turbulence…
Ephemeral Antibubbles: Spatiotemporal Evolution from Direct Numerical Simulations
Nairita Pal, Rashmi Ramadugu, Prasad Perlekar +1
Antibubbles, which consist of a shell of a low-density fluid inside a high-density fluid, have several promising applications. We show, via extensive direct numerical simulations (…
Surface tension as the destabiliser of a vortical interface
Rashmi Ramadugu, Prasad Perlekar, Rama Govindarajan
We study the dynamics of an initially flat interface between two immiscible fluids, with a vortex situated on it. We show how surface tension causes vorticity generation at a gener…
Paths to caustic formation in turbulent aerosols
Jan Meibohm, Vikash Pandey, Akshay Bhatnagar +4
The dynamics of small, yet heavy, identical particles in turbulence exhibits singularities, called caustics, that lead to large fluctuations in the spatial particle-number density,…
Pattern stabilisation in swarms of programmable active matter: a probe for turbulence at large length scales
Pankaj Popli, Prasad Perlekar, Surajit Sengupta
We propose an algorithm for creating stable, ordered, swarms of active robotic agents arranged in any given pattern. The strategy involves suppressing a class of fluctuations known…
Coarsening in the two-dimensional incompressible Toner-Tu equation: Signatures of turbulence
Navdeep Rana, Prasad Perlekar
We investigate coarsening dynamics in the two-dimensional, incompressible Toner-Tu equation. We show that coarsening proceeds via vortex merger events, and the dynamics crucially d…
Liquid velocity fluctuations and energy spectra in three-dimensional buoyancy driven bubbly flows
Vikash Pandey, Rashmi Ramadugu, Prasad Perlekar
We present a direct numerical simulation (DNS) study of pseudo-turbulence in buoyancy driven bubbly flows for a range of Reynolds ($\Rey$) and Atwood ($\At$) numbers. We study the…