A sharp interface Cartesian grid hydrocode

Abstract

Dynamic response of materials to high-speed and high-intensity loading conditions is important in several applications including high-speed flows with droplets, bubbles and particles, and hyper-velocity impact and penetration processes. In such high-pressure physics problems, simulations encounter challenges associated with the treatment of material interfaces, particularly when strong nonlinear waves like shock and detonation waves impinge upon them. To simulate such complicated interfacial dynamics problems, a fixed Cartesian grid approach in conjunction with levelset interface tracking is attractive. In this regard, a sharp interface Cartesian grid-based, Ghost Fluid Method (GFM) is developed for resolving embedded fluid, elasto-plastic solid and rigid (solid) objects in hyper-velocity impact and high-intensity shock loaded environment. The embedded boundaries are tracked and represented by virtue of the level set interface tracking technique. The evolving multimaterial interface and the flow are coupled by meticulously enforcing the boundary conditions and jump relations at the interface. In addition, a tree-based Local Mesh Refinement scheme is employed to efficiently resolve the desired physics. The framework developed is generic and is applicable to interfaces separating a wide range of materials and for a broad spectrum of speeds of interaction (O(km/s)). The wide repertoire of problems solved in this work demonstrates the flexibility, stability and robustness of the method in accurately capturing the dynamics of the embedded interface. Shocks interacting with large ensembles of particles are also computed. Abstract Approved: Thesis Supervisor ACKNOWLEDGEMENTS It is my pleasure to thank those who made this thesis possible. First and foremost, I owe my deepest and sincere gratitude to my thesis supervisor, Prof. H.S. Udaykumar, without whose guidance and constant encouragement this work would have been entirely impossible. His endless patience and professional acumen are undeniably the reason for instilling inspiration and reinforcing confidence in me. I have interacted with him both at personal and professional levels, and I am grateful for the invaluable lessons that I have learned from these interactions. I consider myself extremely fortunate to have him as my thesis supervisor and I undeniably attribute the success of this thesis to his guidance. I would also like to extend my sincere gratitude to all the members of my thesis committee. Their painstaking effort in reading my thesis, the insightful suggestions and the noteworthy advice are greatly and immensely appreciated. Special thanks to my friend Haribalan Kumar for helping me compiling the figures and movies presented in this thesis, and not to mention his excellent culinary skills that made my stay supremely comfortable. I should also thank all the past and the present members of my lab and friends who have made this journey a pleasant and an enjoyable one. I would also like to thank the staff members of the Department of Mechanical Engineering, ...

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