Engineering topics

Schwarzkopf, John Dennis

Publications and source records attributed to Schwarzkopf, John Dennis.

3 records

DOE OSTI2023

Using Taylor Green Vortex to Assess Modeling Turbulence Transition

The Taylor Green Vortex problem is an interesting problem to study the transition from laminar flow to fully developed turbulence. The problem consists initially of large-scale vortices that interact and eventually form smaller vortices that create a cascade of energy from larger scales to smaller scales. This document describes a) when fully developed turbulence occurs, and b) the scale separation in the inertial range. In addition, the resolution needed to capture perturbations in transitional flow is also proposed.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2022

The temperatures of ejecta transporting in vacuum and gases

In this work, we measure continuous thermal radiance from evolving clouds of liquid metal fragments ejected into vacuum, nonreactive, and reactive gas. We implement a model for the thermalization of the ejecta and gas and use this to constrain the absolute temperature of the ejecta cloud. This model enables further analyses of ejecta thermal behavior under a variety of conditions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2022

A simple hydride model for cerium ejecta particles

Cerium ejecta particles form after a shock wave impacts a cerium plate with a known roughness or prescribed surface perturbation. When these particles are ejected into hydrogen or deuterium gas the material reacts exothermically and raises the temperature of the particle relative to the gas. A simple model is developed, assuming that the particle remains intact and spherical, to capture the heat and mass transfer that occurs during this process. Model performance is evaluated by comparing with cerium ejecta experiments where the particles are ejected into deuterium gas at initial pressures of 4 and 8 atm. Overall, the model is able to capture the approximately 400 K increase in particle temperature above the surrounding gas temperature.

36 MATERIALS SCIENCE↗