Mechanical Engineering ETDs

Nyssa Gilkey

Publication Date

7-12-2014

Abstract

The simulation of particle resuspension from a surface due to shock passage and subsequent piston flow presents a means to analyze the post-shock conditions of an environment, such as after a dirty' bomb is detonated. This computational model is based on the 'Rock'n Roll' models of particle detachment by Reeks, Reed, and Hall. The attractive forces used in the model are based on measurements by Truman et al. (2011). The simplifying assumptions of this model are: the simulation is two-dimensional, the particles are perfect spheres of identical size and are arranged in a hexagonal pattern in a bed of specified length and height. Each particle is categorized as being in one of five situations with respect to surrounding particles. These situations are used to model the forces and moments acting on the particles for resuspension. A random particle arrangement was generated within MATLAB, as well as a visual display of the particle layout as the shock wave passes over the particles. The model employs a turbulent velocity profile acquired from a STAR-CCM+ simulation with randomly-varying attractive forces between particles. Particle rolling and the dynamics of resuspending particles are computed during the passage of the shock and its following piston flow. A variety of multi-particle interactions was observed. Particles 'zippered off' along the direction of the flow. Mountains and canyons were eroded away due to either strongly-attracted or weakly-attracted particles. After the shock passes over the particle bed, predictions reveal that all particles are detached above a certain height due to high velocity piston flow. The simulation also predicts the percentage of particles resuspended when exposed to the shock.'

Keywords

particles, resuspension, normal shock

Degree Name

Mechanical Engineering

Level of Degree

Masters

Department Name

Mechanical Engineering

First Committee Member (Chair)

Poroseva, Svetlana

Second Committee Member

Razani, Arsalan

Sponsors

Defense Threat Reduction Agency

Document Type

Thesis

Language

English

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