A5067192020- Fluid Dynamics and Turbulent Flows
- Particle Dynamics in Fluid Flows
- Laser-Plasma Interactions and Diagnostics
- Combustion and Detonation Processes
- Computational Fluid Dynamics and Aerodynamics
- Energetic Materials and Combustion
- Gas Dynamics and Kinetic Theory
- Combustion and flame dynamics
- Fluid Dynamics and Heat Transfer
- Plasma and Flow Control in Aerodynamics
- Astro and Planetary Science
- Laser-induced spectroscopy and plasma
- Magnetic confinement fusion research
- Aeolian processes and effects
- Aerodynamics and Acoustics in Jet Flows
- Rocket and propulsion systems research
- Laser-Matter Interactions and Applications
- Spacecraft Design and Technology
- Wind and Air Flow Studies
- Aerosol Filtration and Electrostatic Precipitation
- Electrohydrodynamics and Fluid Dynamics
- Atmospheric and Environmental Gas Dynamics
- Methane Hydrates and Related Phenomena
- Oceanographic and Atmospheric Processes
- Meteorological Phenomena and Simulations
Los Alamos National Laboratory
2010-2022
University of Florida
2015-2022
Lawrence Livermore National Laboratory
2022
University of Maryland, College Park
2022
Computational Physics (United States)
2022
Embry–Riddle Aeronautical University
2017-2021
University of Waterloo
2020
University of the West Indies System
1983
In this work, the particle jetting behavior in a blast-driven dense bed is studied at early times. Four-way coupled Euler–Lagrange simulations are performed using high-order discontinuous Galerkin spectral element solver with Lagrangian solver, wherein inter-particle collisions resolved discrete method collision model. Following experiments of Rodriguez et al. [“Formation cylindrical shock tube,” Shock Waves 23(6), 619–634 (2013)] and Osnes [“Numerical simulation jet formation induced by...
Reynolds-Averaged Navier–Stokes (RANS) models remain the most common design tool in a wide variety of fluid mixing applications. This includes variable-density turbulent as occurs inertial confinement fusion. The present work extends validation BHR-2 RANS model for turbulence to two-dimensional Rayleigh–Taylor test case, “tilted-rig.” combined effects bulk motion and behavior are discussed, several quantities interest shown demonstrate capability four-equation describe this type mixing. More...
A new approach to generate initial conditions for RANS simulations of Rayleigh–Taylor (RT) turbulence is presented. The strategy provide profiles turbulent model variables when it suitable the be started, and then use these initialization. generation variable achieved with a two-step process. In first step, nonlinear modal assuming small amplitude perturbations, incompressible inviscid fluids used track growth modes that exist in given perturbation spectrum, also generated by mode...
Recent experiments have shown that when a dense layer of solid particles surrounding high-energy reactive material is explosively dispersed, the cluster locally leading to jetlike patterns. The formation these coherent structures has yet be fully understood and believed its origin in early moments explosive dispersal. This paper focuses on an dispersal particles. In particular, effect initial perturbations both gas particulate phase investigated, considering heavy with low particle volume...
The relation between the form of a body force driving turbulent shear flow and dissipation factor β = ϵℓ/ U 3 is investigated by means rigorous upper bound analysis direct numerical simulation. We consider unidirectional steady forcing functions in three-dimensional periodic domain observe that infinite Reynolds number on displays same qualitative behaviour as computationally measured at finite profile varied. also compare mean profiles with Stokes for forcing. are strikingly similar numbers...
Abstract Pollen descriptions of four common mangrove species Rhizophora mangle L. (Rhizophoraceae), Avicennia germinans (L.) (Avicenniaceae), Conocarpus erectus and Laguncularia racemosa Gaertn. f. (Combretaceae) are presented. These dominate the communities in coastal wetlands Caribbean their pollen is peat cores taken from such deposits. The identification grains fairly easy as investigated have characteristic pollen, however it difficult to distinguish between when found fossil material....
A research area emerging in the multiphase flow community is study of shock-driven instability (SDMI), a gas–particle analog traditional fluid-fluid Richtmyer–Meshkov (RMI). In this work, we interaction planar air shocks with corrugated glass particle curtains through use numerical simulations an Eulerian–Lagrangian approach. One objective to compare simulated comparable set shock tube experiments performed analyze RMI gas curtain. The are match experimental Mach numbers and perturbation...
We extended the Goncharov model [V. N. Goncharov, Phys. Rev. Lett. 88, 134502 (2002)] for nonlinear Rayleigh-Taylor instability of perfect fluids to case Rivlin-Ericksen viscoelastic [R. S. Rivlin and J. L. Ericksen, Rat. Mech. Anal. 4, 323 (1955)], with surface tension. For instability, viscosity, tension, viscoelasticity decrease exponential growth rate predicted by linear stability analysis. In particular, we find that viscosity tension terminal bubble velocity, whereas is found have no...
Explosive dispersal of particles is a complex multiphase phenomenon that has yet to be fully understood. As the particle cloud disperses at high speed, it experiences instabilities related Richtmyer-Meshkov (RM) and Rayleigh-Taylor (RT) when interacting with blast-wave structure. This paper reports results numerical experiment where effect bimodal perturbations in initial volume fraction studied. Results indicate signature perturbation profile remains throughout observed time, adding...
Accurate simulation of the complex flow following detonation an explosive material is a challenging problem. In these flows, products must be treated as real gas while surrounding air ideal gas. As process unfolds and blast wave moves into ambient air, expand outward interact with creating mixture region. this region, both state equations for satisfied. One most accurate, yet computationally expensive, methods to handle problem algorithm that iterates between until pressure temperature reach...
The tilted rig experiment is a derivative of the rocket designed to study mixing fluids by Rayleigh-Taylor instability. In latter experiment, tank containing two different densities accelerated downwards between parallel guide rods motor. Misalignment density and pressure gradients trigger instability leading turbulence fluids. inclined few degrees off vertical before firing, creating slanted initial perturbation interface. purpose was help with calibration models, as it unique...
The tilted rig experiment is a derivative of the rocket designed to study mixing fluids by Rayleigh–Taylor instability. In this experiment, tank containing two different densities accelerated downwards between parallel guide rods motor. inclined few degrees off vertical force two-dimensional Thus, can help calibrate models. Simulations experiments using Los Alamos National Laboratory’s hydrocodes are reported. Both codes, xRAGE and FLAG, multidimensional, multimaterial, massively parallel,...
Variable-density turbulent mixing is found in a wide variety of applications, and modeling these effects continuing challenge. Reynolds–Averaged Navier–Stokes models remain the most common design tool fields. This paper extends validation RANS for variable-density turbulence to two-dimensional Rayleigh–Taylor test case. The combined bulk fluid motion model behavior are discussed several metrics shown demonstrate ability four-equation describe this class flows.
Accurate simulation of the complex flow following detonation an explosive material is a challenging problem. In these flows, products must be treated as real gas while surrounding air ideal gas. As expand outward from point, they mix with ambient and create mixing region where both state equations satisfied. One most accurate, yet computationally expensive, methods to handle this problem algorithm that iterates between until pressure thermal equilibrium are achieved inside each computational...