Slowing sloshing in space
Slowing sloshing in space lead image
Controlling fluids in microgravity is much more challenging than on Earth. Absent gravity’s intervention, liquids form large bubbles, easily adhere to surfaces, and are significantly affected by small perturbations. Once in motion, fluids sloshing in a container take longer to relax without the restoring force of gravity. These oscillations can interfere with flight dynamics in the same way a glass of sloshing water can topple over.
Yet liquids like propellent and water are necessary in microgravity, so sloshing reduction techniques are vital. Peromingo et al. simulated a combination of sloshing reduction methods to achieve the fastest return to equilibrium.
“Currently, the most widespread method is the introduction of baffles in the fluid system,” said author Pablo Salgado Sánchez. “These dampers, which can be static, moving, or controlled by actuators, increase the friction with the fluid and reduce fluid motion. Other relatively novel approaches use magnetic fields or apply temperature modulation to the liquids. The principle behind temperature modulation is to generate Marangoni flows that counteract the original sloshing motion.”
The team utilized computer simulations to identify the ideal combination of baffle shape, number, and arrangement for a liquid in a rectangular tank. They then introduced temperature modulation, and with both strategies at work, the team reduced sloshing decay time by more than 80%.
“Sloshing reduction can be beneficial for many space applications,” said Salgado Sánchez. “These methods can be used in propellant tanks, water storage systems or other liquid reservoirs, and life support systems. The relevant applications are not restricted to space missions, of course, but include numerous terrestrial systems as well, like trucks transporting liquid, manned and unmanned air vehicles, and offshore oil extraction plants.”
Source: “Sloshing reduction in microgravity with passive baffles: Design, performance, and supplemental thermocapillary control,” by C. Peromingo, P. Salgado Sánchez, D. Gligor, A. Bello, and J. Rodríguez, Physics of Fluids (2023). The article can be accessed at https://doi.org/10.1063/5.0174635 .
