About Ryan

J. Mike Walker '66 Department of Mechanical Engineering

Ph.D. Candidate in Mechanical Engineering

Dissertation: "Reactive Metal Ejecta Formation and Breakup"

Committee:

Drs. Jacob McFarland (chair), Iman Borazjani, Matt Pharr, and Lin Shao

Gallogly College of Engineering

B.S. in Mechanical Engineering

Awarded with Special Distinction

Texas A&M University

Graduate Research Assistant | Fluids Mixing at Extreme Conditions Lab

Advisor: Dr. Jacob McFarland

Los Alamos National Laboratory

Student Researcher | XCP-4 Continuum Models and Numerical Methods

Advisors: Dr. Jonathan Regele, Dr. Frederick Ouellet

University of Oklahoma

Undergraduate Research Assistant | Biomechanics and Biomaterials Design Lab

Advisor: Dr. Chung-Hao Lee

University of Oklahoma

Undergraduate Research Assistant | Biomedical Engineering Lab

Advisor: Dr. Chenkai Dai

Peer-Reviewed Journal Publications

• 1. Myers, R. J., Ouellet, F., Regele, J. D., and McFarland, J. A., "A Stress-Based Fracture Model for Reacting Metal Ejecta," Journal of Applied Physics, Accepted for publication, 2026.
• 2. Zargarnezhad, H., Myers, R. J., and McFarland, J. A., "Particle size effects in multiphase Rayleigh–Taylor instability," Physics of Fluids, Volume 37, Issue 4, 2025, 043302. DOI
• 3. Zargarnezhad, H., Myers, R. J., Speck, A. K., and McFarland, J. A., "Radiation driven-dust hydrodynamics in late-phase AGB stars," Astronomy and Computing, Volume 45, 2023, 100766. DOI

Selected Presentations

• Myers, R. J. et al., "Secondary Breakup of Reactive Metal Ejecta Particles," presented at the JCRNS Workshop, College Station, TX, Dec 2025.
• Myers, R. J. et al., "Stress Analysis of a Reacting Hydride Ejecta Particle," presented at the JCRNS Workshop, College Station, TX, Dec 2024.
• Myers, R. J. et al., "Early Simulations of a Reacting Metal Ejecta Particle in Still Gas," presented at the APS DFD Meeting, Salt Lake City, UT, Nov 2024.
• Myers, R. J. et al., "Creating Physics Mechanisms for Simulating Reactive Metal Ejecta for Use in Particle Models," poster presented at the Texas A&M National Labs Office Reception, Mar 2024.
• Myers, R. J. et al., "Analysis of a Reaction Mechanism for Use in Ejecta Particle Simulations," presented at the APS Shock Compression of Condensed Matter, Chicago, IL, June 2023.
• Myers, R. J. et al., "Implementation of Diffusion and Reaction Mechanisms for Reactive Ejecta Simulations," poster presented at the APS DFD Meeting, Indianapolis, IN, November 2022.

Multi-Layered Richtmyer-Meshkov Instabilities

Investigating a historically overlooked variable, this research examines how surface finish dictates the formation and subsequent dynamics of reactive metal ejecta. By focusing on the initiation and growth rates of the Richtmyer-Meshkov instability, the work identifies how initial surface morphology influences secondary particle production. This effort implements simulations across a broad range of scenarios to establish a robust framework capable of predicting these effects in practical applications. Ultimately, this framework establishes a definitive connection between initial surface conditions and the macroscopic production of reactive metal particles in extreme environments.

Stress-Based Fracture Models for Reactive Ejecta

A major predictive advancement in the field, this work implements a theoretical stress evolution model capable of analyzing millions of particles in large-scale ejecta simulations. By accounting for the size and temperature dependent dynamics of the hydride shell, which were often overlooked in prior research, the model enables a more physically grounded representation of reactive ejecta. The framework performs fracture analysis for Lagrangian point particles within an Arbitrary Lagrangian-Eulerian hydrocode where experimental conditions are replicated for validation. Replicating these conditions bolsters the model's reliability for predicting fracture behavior across vast populations of reactive particles.

Resolved Hydriding Particle Simulations

Utilizing mesh-resolved simulations, this research examines the interaction between chemical reactions and physical breakup in reactive metal ejecta. In experimental settings, these particles evolve violently with the formation of a solid hydride shell. Because the minute scale of the particles makes direct measurement of fracture and breakup difficult, computational simulations are employed to characterize their evolution. The work centers on extensive code development and implementation within an Arbitrary Lagrangian-Eulerian hydrocode to bridge these complex physical processes. By integrating material modeling and reaction product dynamics, the effort attempts to clarify how product shell growth directly influences the mechanical integrity and fragmentation of individual particles.

Qualitative Physical Examples

You might notice I have some apps here that show relatively simple phenomena in fluid mechanics. I personally find it helpful to have a qualitative example to visualize the effects of, say, an equation. Being a visual learner, I've found it a bit rough in more abstract classes where equations usually come first and examples are often an afterthought. I would love to keep making these as pedagogical tools in the future. If you have any comments or ideas, please reach out. I am always interested in new ways to create outreach in my field!

Hobbies and Pastimes