Work

Long-term microgravity experiments reveal a new mechanism for particle aggregation in suspension

Year: 2025

Type: article

Abstract: Microgravity experiments on board the International Space Station, combined with particle-resolved direct numerical simulations, were conducted to investigate the long-term flocculation behavior of clay suspensions in saline water in the absence of gravity. After an initial homogenization of the suspensions, different clay compositions were continuously monitored for 99 days, allowing a detailed analysis of aggregate growth through image processing. The results indicate that the onboard oscillations (g-jitter) may have accelerated the aggregation process. Aggregate growth driven by these oscillations is found to occur at a faster rate than aggregation caused by Brownian motion. Complementary numerical simulations confirm this hypothesis and also demonstrate that parameters such as the oscillation amplitude and the solid volume fraction influence growth acceleration. These findings highlight that oscillations may act as a previously unrecognized mechanism that contributes to particle aggregation in fluids.

Source: npj Microgravity

DOI: 10.1038/s41526-025-00523-7

Authors: Fabian Kleischmann, Bernhard Vowinckel, Eckart Meiburg, Paolo Luzzatto-Fegiz

Institutions: Technische Universität Dresden, University of California, Santa Barbara

Language: English

Topic: Particle Dynamics in Fluid Flows

Subfield: Ocean Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $3,690