Keywords

CFD, Hypersonic, Cavitation, Droplet

Abstract

This dissertation investigates the formation and evolution of cavitation within liquid droplets subjected to shock wave interactions, with emphasis on internal pressure wave focusing as a fragmentation mechanism. A numerical framework is developed in which high-resolution Volume-of-Fluid (VoF) simulations resolve shock transmission into spherical, cylindrical, and cubic water droplets across a range of flow conditions. The resulting pressure histories at droplet centers are extracted and post-processed using the Rayleigh–Plesset equation to model the dynamics of spherical vapor bubbles.

The modeling framework is validated against established benchmarks, including canonical shock tube behavior, shock-droplet interaction studies, and experimental cavitation observations. A series of parametric studies is conducted across Mach number (1.5–7), ambient pressure (20–100 kPa), and droplet diameter (0.5–5 mm), revealing how droplet geometry and flow conditions influence cavitation onset and severity. Regression models and scaling laws are developed to predict cavitation-relevant metrics, including minimum pressure, maximum bubble radius, and cavitation time, as functions of nondimensional parameters.

A cavitation regime map is proposed, highlighting a “zone of applicability” in which internal cavitation is expected to precede and dominate droplet breakup. These findings offer a new perspective on compressible multiphase breakup, challenging traditional surface-driven paradigms and providing predictive tools for evaluating cavitation risk in high-speed, droplet-laden environments.

Completion Date

2025

Semester

Summer

Committee Chair

Kinzel, Michael

Degree

Doctor of Philosophy (Ph.D.)

College

College of Engineering and Computer Science

Department

Mechanical and Aerospace Engineering

Format

PDF

Identifier

DP0029537

Language

English

Document Type

Thesis

Campus Location

Orlando (Main) Campus

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