Date of Award

8-22-2018

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Department of Mathematics and Statistics

First Advisor

Benjamin F. Akers, PhD.

Abstract

High energy lasers have many applications, such as in aerospace, weapons, wireless power transfer, and manufacturing. Fluid-laser interaction is important to predicting power at receiver, and other measures of laser beam quality. Typically the carrying medium of the laser is modeled statistically. This dissertation describes a novel method of coupling fluid dynamics to beam propagation in free space. The coupled laser-fluid solver captures dynamic interaction of fluid temperature and beam intensity. Ultimately, the model captures the effects of fluid convection in the laser intensity-field. Boundary conditions play an important role for fluid dynamics, more so than for beam dynamics. Simulation convergence and time performance are compared for three fluid boundary conditions: periodic boundary conditions, finite box domain, and an open boundary condition. Scintillation is included in the final simulations. Scintillation is an important factor in laser beam quality. It is usually incorporated via phase-screens on the beam alone. A unique hybrid volumetric phase-screen model is developed to simulate laser- fluid interaction in the presence of small turbulence. The hybrid model is simulated and results of simulations, where scintillation is asymptotically incorporated into the coupled fluid-beam simulation, are presented.

AFIT Designator

AFIT-ENC-DS-18-S-003

DTIC Accession Number

AD1063252

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