Student Name: Luca Silveri

Advisor: Dr. Alvaro Romero-Calvo

Milestone: MS Thesis Final Examination (Defense)

Degree Program: Aerospace Engineering

Title: Low-Gravity Sloshing in Spherical Tanks: Experimental Investigation Toward Numerical and Analytical Modeling

Abstract: Uncontrolled sloshing in spacecraft propellant tanks can severely disturb vehicle attitude and dynamics, jeopardizing critical maneuvers such as docking, proximity operations, pointing, rendezvous, and in-orbit refueling. Despite decades of research, the dynamics of low-gravity sloshing remain insufficiently understood and difficult to model with reliability. Numerous CFD and analytical models have been proposed over the years, but their validation relies on experimental data that remain limited and incomplete. In this context, this thesis presents: (i) a new experimental dataset on low-gravity sloshing in a spherical tank; (ii) a numerical CFD framework and an analytical spherical pendulum model for simulating low-gravity free contact line fluid motion; and (iii) the development of numerical and analytical models for contact angle hysteresis. The experimental dataset, originating from the SILA (Sloshing Imaging and Load Analysis) payload, shows low- to large-amplitude sloshing in a spherical tank for a range of Bond numbers between 0 and 41. The force exerted on the tank walls is recorded, and the position of the center of mass is reconstructed from free surface tracking to analyze the fluid’s response in both time and frequency domains. Video imaging and Bond number evolution are reported for a better characterization of the low-gravity environment and transitions between high and low gravity. A numerical Volume of Fluid setup is implemented in ANSYS Fluent, and the low-gravity steady-state behavior is validated for constant values of contact angles through the simulation of fluid reorientation. To capture the dynamics of fluid motion, the development of a User Defined Function modeling the contact angle hysteresis is initiated. Similarly, the analytical model of the spherical pendulum is implemented in MATLAB to simulate free contact line motion in low gravity, and the development of a two-pendulum model is initiated to capture the dynamics given by the contact angle hysteresis.

Date and time: 2025-12-01, 11.30 am

Location: MK 317 Conference Room

Committee:
Dr. Alvaro Romero-Calvo (advisor), School of Aerospace Engineering
Dr. Claudio V. Di Leo, School of Aerospace Engineering
Dr. Joseph Oefelein, School of Aerospace Engineering
, 
, 
,