Simulation of Fluid Sloshing in High-Acceleration Environments for Aerospace Applications

Sloshing fluid inside vehicle containers is a serious concern for engineers, manufacturers, and consumers alike, causing multiple problems in an aircraft's structural stability, vibrations, and acoustics. Fluid sloshing refers to the movement of liquid within a container due to acceleration forces, a phenomenon particularly critical in aerospace applications. The problem of fluid sloshing is widespread among aerospace and automotive sectors. A notable example is the failure of SpaceX’s Falcon 1 Rocket, which did not reach orbit due to unforeseen oscillations in the upper stage caused by sloshing in the liquid oxygen tank. As the aerospace industry continues to rapidly expand, the impact of fluid sloshing will perpetuate, creating more problems for future engineers to overcome. The continued research in fluid sloshing is a top priority for engineers in aerospace fields because of the unknown issues and complications that will arise. Baffles and pressurized tanks relieve the issue of sloshing, but as new technology continues to develop, these solutions will become outdated if no further research occurs. The rapidly increasing power of computational fluid dynamics (CFD) simulations and mathematical models allows engineers to solve problems before any catastrophic failure occurs. Therefore, a comprehensive understanding of the causes and effects of fluid sloshing will allow engineers to improve designs of fuel containers and baffles to mitigate the destabilizing effects of sloshing. In this paper, an in depth analysis of CFD simulations is employed to model the sloshing of a fluid dynamics experimental payload. The payload experiment is designed for The University of Georgia’s International Rocketry Engineering Competition (IREC) team, where a team of engineers is developing a Level 3-certified high-powered rocket to reach 10,000 feet. As the model rocket travels, the large accelerations and forces experienced affect the payload, causing a sloshing to occur at different frequencies. The time from liftoff to the completed burnout of the solid rocket motor is taken to measure the sloshing of the payload, a critical phase for analyzing sloshing behavior. Utilizing the altitude, velocity, and acceleration data from the UGA IREC launch, a detailed simulation of the sloshing container can be constructed. The data collected during the acceleration phase of the rocket serve as the basis for simulating fluid sloshing. These acceleration profiles are applied to ANSYS, to replicate the sloshing dynamics inside a fuel tank under similar conditions. Through this process, the simulation provides key insights on the oscillation frequencies, pressure variations, and the structural loads induced by the fluid motion. The simulation enhances the understanding of sloshing mechanics, along with gaining critical data needed to optimize baffles. Ultimately, these findings aid in developing more robust aerospace fuel tanks capable of withstanding the destabilizing effects of fluid movement in high acceleration environments.