Improve passive flow control while limiting flow resistance

Determine whether passive flow-control concepts for gravity-driven granular pipe flow can be improved by increasing spiral particle motion while limiting the accompanying flow resistance.

Background

The paper uses discrete element simulations to relate spiral particle motion to suppression of density waves in granular pipe flow. A helically curved pipe was found to generate stronger spiral motion than a helical wall texture and, over the investigated parameter range, to improve both flow homogeneity and mean transport velocity. However, generating stronger transverse motion may also increase resistance and wall loading. The authors therefore leave unresolved whether future passive designs can enhance spiral motion without incurring these associated penalties.