9/8/2025 Taylor Parks
Written by Taylor Parks
MechSE Professor Leonardo Chamorro and Professor James Best from the Department of Earth Science & Environmental Change in the School of Earth, Society & Environment at Illinois have been awarded a grant from the National Science Foundation to investigate the behavior of clay-laden flows under intense, unsteady shear—one of the least understood phenomena in fluid mechanics.
Clay suspensions, or clay suspended in fluid flow, are central to processes that shape landscapes and affect engineered systems, from sediment transport in rivers and estuaries to erosion control and structure performance. However, the hydrodynamics of transitional clay-laden turbulence remain poorly characterized. Chamorro and Best are working to develop a systematic approach to uncover how clay concentration alters turbulence dynamics, flow stability, and boundary layer development under high-frequency, oscillatory shear.
The team will use Laponite, a synthetic clay that yields optically transparent suspensions, to capture turbulence, particle dispersion, and wall-flow interactions through non-intrusive diagnostics.
“This NSF award allows us to move beyond description and toward prediction,” Chamorro said. “Our objective is to establish a rigorous approach that links clay concentration, unsteady shear, and turbulence dynamics, a knowledge that can fundamentally reshape how natural and engineered flow systems are understood and designed.”
Over the upcoming year, the pair and team member Soohyeon Kang will investigate the fundamental physics governing turbulence transitions in water-clay flows with the goals of identifying critical conditions for these transitions and establishing the first scaling laws that link clay concentration, oscillatory forcing, and turbulence onset. Using a custom-built oscillatory flume, the team will prepare and validate Laponite suspensions and conduct systematic experiments across a range of clay concentrations, oscillation frequencies, and amplitudes. They will use advanced flow diagnostics, including particle image velocimetry and particle tracking velocimetry, to capture the onset and structure of turbulence in freestream and near-wall regions.
Chamorro credits his interdisciplinary collaboration with Best as being a significant strength for the study. “By integrating perspectives from engineering and the geosciences, this project creates a unique platform to rethink how fine sediments behave in motion,” he said. “Such insights are essential not only for advancing fundamental science but also for addressing urgent technological and environmental challenges.”
Leonardo Chamorro is the Principal Investigator for the Renewable Energy & Turbulent Environment Group. The team’s NSF grant is titled, “Quantifying Unsteady Shear Effects on Clay-Loaded Media: Stability and Surface Roughness Implications.”