Master's Thesis Proposal

Luca Silveri

(Advisor: Prof. Romero-Calvo)

"Experimental validation of low-gravity slosh models for spherical tanks"

On

Friday, August 22 

11:30 a.m.

ESM Room 108

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, the proposed thesis aims to present: a new experimental dataset on low-gravity sloshing in a spherical tank, the validation of a CFD setup against the experimental data, and a study on the accuracy of the pendulum and negative-mass analytical models based on the experimental and numerical data. The experimental dataset originates from the SILA (Sloshing Imaging and Load Analysis) payload, designed for a Zero-G parabolic flight campaign and featuring a spherical tank partially filled with water. The results show how the applied acceleration field influences the fluid motion and the resulting force exerted on the tank walls along a single axis. The Bond number is mapped to characterize the transition phases between low-gravity and high-gravity regimes. The CFD model is developed in ANSYS Fluent. It tracks both the time history of the force exerted on the tank walls along a single axis and the motion of the fluid free surface, enabling direct comparison with the experimental dataset. A sensitivity analysis is performed for a simpler case: a 30-degree inclined free-surface under 1g conditions. 

Future work includes numerically simulating the most relevant low-gravity parabolas and developing the pendulum and negative-mass analytical models in the MATLAB environment. The accuracy of these reduced-order models will then be assessed against the CFD simulation results, both under low-gravity conditions and during the transition phases between high and low gravity.

Committee

• Prof. Alvaro Romero-Calvo – School of Engineering (advisor)
• Prof. Claudio V. Di Leo – School of Engineering
• Prof Joseph Oefelein – School of Engineering