Rheology of confined granular flows : from gas to glass
نویسندگان
چکیده
An intriguing feature of granular matter is the close coexistence of solid-like regions and liquid-like flows. We study steady, fully-developped, granular flows confined between parallel vertical sidewalls. The sidewall friction stabilizes the underlaying heap at an inclination exceeding the angle of repose and increasing with flow rate. Our experiments reveal, in agreement with numerical simulations, that the volume fraction varies strongly in the flowing layer. We show that the resultant sidewall friction is not constant either. Above a critical depth, solid volume fraction, velocity and friction evolve on a common length scale. Below, the system appears to behave as a glass engaged in creeping flow.
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