Akhil V. Marayikkottu

National Energy Technology Laboratory | NETL

This paper presents an overlay-based one-way coupled Eulerian–Lagrangian computational approach designed to investigate the dynamics of particulate phases in extreme high-speed, high-altitude flight conditions characterized by very low particulate mass loading. Utilizing the Direct Simulation Monte Carlo method to generate accurate gas flow fields,...

An overlay-based one-way coupled Eulerian-Lagrangian solver is used to simulate dilute hypersonic gas-solid flows characterized by low particulate mass loading. Utilizing the Direct Simulation Monte Carlo (DSMC) method to generate accurate gas fields, this study explores flows over a canonical sphere-cone geometry. The general gas-solid phase coupl...

In the study of gas-particulate multiphase systems, the flow of high-speed gas through a distribution of solid particulates is of utmost importance. While these aerodynamically interacting systems have been extensively studied for low-speed gas flows in the gas continuum regime, less attention has been given to high-speed systems where non-continuu...

Although particle–laden electrostatic discharges are widely used in laboratories as well as in industrial applications, the mechanism of particle lifting for particles initially at rest in such highly unsteady systems is not well understood. A multiphase gas–particle solver is developed using the multiphase particle-in-cell (MP-PIC) approach to emu...

For multiphase flows with dense particulate distributions, the effect of momentum and energy back coupling with the underlying gas flow and inter-particle interaction is significant. In the present work, we present our preliminary work towards developing a two-way coupled solver on the original framework of the FLASH code. Particle force models tha...

This study utilizes in-situ data of stratospheric particle size distributions to understandparticle-surface impacts at hypersonic flight conditions. Simulations are performed to trackLagrangian particles through the flow field and statistically gather characteristics of particlesthat impact the surface. Probability density functions in terms of sur...

Two approaches for numerically modeling shock-dominated gas-particle multiphase flowsare introduced. The micron-scale simulations using the Direct Simulation Monte Carlo(DSMC) method were found to be efficient in developing mobility parameters for compli-cated particulate geometries and aerodynamically interacting particulate systems. For largeleng...

Although the mobility or transport parameters, such as lift drag and pitching moments for regular-shaped particulates, are widely studied, the mobility of irregular fractal-like aggregates generated by the aggregation of monomers is not well understood. These particulates which are ubiquitous in nature, and industries have very different transport...

A hypersonic boost-glide trajectory is calculated for an initial altitude of $60$ km and a velocity after boost of 3.7 km/s. The hypersonic vehicle travels 2750 km before it reaches its destination over a flight time of 21.75 minutes. The aero-heating effects of a conically shaped hypersonic vehicle on the re-entry trajectory is calculated using a...

The flow of rarefied gas through dense monodispersive spherical particle distribution is investigated using the Direct Simulation Monte Carlo (DSMC) method. The complicated flow established in the vicinity of the particle distribution generates variability of single particle fluid-induced forces through complex aerodynamic interactions. For the sam...

Even though the interaction of blast waves with dense particle distributions is ubiquitous in nature and in industry, the underlying physics of the multiphase system evolution is not clearly understood. A canonical multiphase system composed of an embedded monodisperse distribution of spherical particles in a spherical, high-energy gaseous charge i...

Although particle-laden electrostatic discharges are widely used in research as well as in industrial applications, the mechanisms of particle lifting for a particle initially at rest in such highly unsteady flows are not well understood. A multiphase plasma flow is modeled by solving the continuum conservation equations and particles as discrete e...

Particle-laden electrostatic discharges are widely used in research as well as in industrial applications. The mechanism of particle lifting in these highly unsteady flows are not well understood. Modifications are made to the FLASH research code to simulate this multiphase system using the Lagrangian-Eulerian (LE) approach. Various Lagrangian subm...

The paper is aimed at studying the transportation of dust grains in a moving shock/pressure wave generated by electrostatic discharge devices. The current work covers two major aspects of the study. The development of a reasonably accurate electrostatic discharge simulation and the study of transport properties of dust grains using the Direct Simul...

The direct simulation Monte Carlo method is one of the most widely used particle-based methods in solving flows with a large degree of rarefaction. Direct simulation Monte Carlo method finds its place in effectively simulating flows in rarefied regimes like the high-altitude flows and micro/nanoflows. The method, although effective, is prone to sta...

Analysis of microchannel flows using Direct Simulation Monte Carlo (DSMC) method with modified boundary conditions.