English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Granular flow out of a silo is studied experimentally and numerically. Thetime evolution of the discharge rate as well as the normal force (apparentweight) at the bottom of the container is monitored. We show, that particlestiffness has a strong effect on the qualitative features of silo discharge.For deformable grains with a Young's modulus of about $Y_m\approx 40$ kPa in asilo with basal pressure of the order of 4 kPa lowering the frictioncoefficient leads to a gradual change in the discharge curve: the flow ratebecomes filling height dependent, it decreases during the discharge process.For hard grains with a Young's modulus of about $Y_m\approx 500$ MPa the flowrate is much less sensitive to the value of the friction coefficient. Using DEMdata combined with a coarse-graining methodology allows us to compute all therelevant macroscopic fields, namely, linear momentum, density and stresstensors. The observed difference in the discharge in the low friction limit isconnected to a strong difference in the pressure field: while for hard grainsJanssen-screening is effective, leading to high vertical stress near the silowall and small pressure above the orifice region, for deformable grains thepressure above the orifice is larger and gradually decreases during thedischarge process. We have analyzed the momentum balance in the region of theorifice (near the location of the outlet) for the case of soft particles withlow friction coefficient, and proposed a phenomenological formulation thatpredicts the linear decrease of the flow rate with decreasing filling height.

Flow in an hourglass: particle friction and stiffness matter