Gas-Particle Dynamics in High-Speed Flows

High-speed disperse multiphase flows are present in numerous environmental and engineering applications with complex interactions between turbulence, shock waves, and particles. Compared to its incompressible counterpart, compressible two-phase flows introduce new scales of motion that challenge simulations and experiments. This review focuses on gas-particle interactions spanning subsonic to supersonic flow conditions. An overview of existing Mach number-dependent drag laws is presented, with origins from 18th-century cannon firings, and new insights from particle-resolved numerical simulations. The equations of motion and phenomenology for a single particle are first reviewed. Multi-particle systems spanning dusty gases to dense suspensions are then discussed from numerical and experimental perspectives

Direct numerical simulation of noise suppression by water injection in high-speed flows

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143117/1/6.2017-1700.pd

Adjoint-based sensitivity analysis of ignition in a turbulent reactive shear layer

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143014/1/6.2017-0846.pd

A volume-filtered description of compressible particle-laden flows

In this work, we present a rigorous derivation of the volume-filtered viscous compressible Navier–Stokes equations for disperse two-phase flows. Compared to incompressible flows, many new unclosed terms appear. These terms are quantified via a posteriori filtering of two-dimensional direct simulations of shock-particle interactions. We demonstrate that the pseudo-turbulent kinetic energy (PTKE) systematically acts to reduce the local gas-phase pressure and consequently increase the local Mach number. Its magnitude varies with volume fraction and filter size, which can be characterized using a Knudsen number based on the filter size and inter-particle spacing. A transport equation for PTKE is derived and closure models are proposed to accurately capture its evolution. The resulting set of volume-filtered equations are implemented within a high-order Eulerian–Lagrangian framework. An interphase coupling strategy consistent with the volume filtered formulation is employed to ensure grid convergence. Finally PTKE obtained from the volume-filtered Eulerian–Lagrangian simulations are compared to a series of two- and three-dimensional direct simulations of shocks passing through stationary particles

Andreev spin-noise detector

We investigate the possibility to employ magnetic Josephson junctions as magnetic-noise detectors. To illustrate our idea, we consider a system consisting of a quantum dot coupled to superconducting leads in the presence of an external magnetic field. Under appropriate assumptions, we relate the noise in the Josephson current to magnetization noise. At the magnetic field driven $0-\pi$ transition the junction sensitivity as magnetic noise detector is strongly enhanced and it diverges in the zero temperature limit. Moreover, we demonstrate that, if also dot energy is affected by fluctuations, only the magnetic noise channel contributes to Josephson current noise response when the quantum dot is tuned in resonance with superconducting leads.Comment: Review. 14 pages. 3 appendices. 14 figure

A computational study of the effects of multiphase dynamics in catalytic upgrading of biomass pyrolysis vapor

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145281/1/aic16184.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145281/2/aic16184_am.pd