What the study found
The study found that oscillatory rheometry with Fourier transform analysis can separate elastic and viscous behavior in dense granular flow. It also found rheological markers linked to transitions from quasistatic, friction-like flow to dense inertial, fluid-like flow.
Why the authors say this matters
The authors conclude that these characterization criteria are relevant to managing dense granular flows in quasistatic and dense inertial regimes. The study suggests this could help with handling particulate materials in geophysical and industrial settings.
What the researchers tested
The researchers used a chute-flow rheometer, a device for measuring how a material flows under stress, with multimodal sensing. They applied oscillatory shear in a Couette gap and measured torque, wall pressure, and axial flow, then used Fourier transforms and Lissajous-Bowditch plots to analyze the cyclic data.
What worked and what didn't
Torque data normalized to the active mass were converted to specific torque and shear stress and analyzed successfully. Viscoelastic crossovers appeared at relatively low shear rates, and secondary loops appeared at higher shear rates in elastic plots, which the authors describe as consistent with a transition to dense inertial flow. The abstract does not report any failed measurements or negative results.
What to keep in mind
The summary does not describe experimental limits, sample details, or conditions beyond the dense granular flows studied. It also does not provide quantitative thresholds for the reported transitions.
Key points
- Fourier transform rheology was used to decompose dense granular flow data into elastic and viscous components.
- Viscoelastic crossovers were observed at relatively low shear rates, consistent with quasistatic flow.
- Secondary loops in elastic Lissajous-Bowditch plots appeared at higher shear rates, consistent with dense inertial flow.
- The study compared inertial number scaling using specific torque with the conventional pressure-based definition.
- A contour diagram summarized coupling between shear and normal forces in the rheometer.
Disclosure
- Research title:
- Oscillatory measurements distinguish dense granular flow regimes
- Authors:
- Donovan Stumpf, K. Henry, Carl Wassgren, Paul R. Mort
- Institutions:
- Purdue University West Lafayette, Purdue University West Lafayette, Purdue University West Lafayette, Purdue University West Lafayette
- Publication date:
- 2026-04-21
- DOI:
- 10.1122/8.0001057
- OpenAlex record:
- View
Get the weekly research newsletter
Stay current with scholarly research without reading academic papers — one filtered digest, every Friday.