Numerical simulations of dense granular suspensions in laminar flow under constant and varying shear rates

Numerical simulations of dense granular suspensions in laminar flow under constant and varying shear rates

Srinivasan, Sudharsan (University of Limerick)
van den Akker, H.E.A. (TU Delft ChemE/Transport Phenomena; University of Limerick)
Shardt, Orest (University of Limerick)

2021

Using an immersed boundary-lattice Boltzmann method, we investigated the response of dense granular suspensions to time-varying shear rates and flow reversals. The evolution of the relative apparent viscosity and particle structures was analysed. The concentration of solids (ϕ_v) and particle Reynolds numbers (Re_p) were varied over the ranges 6%≤ϕ_v≤47% and 0.105≤Re_p≤0.529. The simulations included sub-grid scale corrections for unresolved lubrication forces and torques (normal and tangential). When ϕ_v surpasses 30%, the contribution of the tangential lubrication corrections to the shear stress is dominant. While for intermediate solids fractions we find weak shear-thinning, we see weak shear-thickening for ϕ_v>40%. We show how the structure and apparent viscosity of a suspension evolves after a reversal of the shear direction. For 47% solids, simulations with step changes in the shear rate show the effects of the previous shear history on the viscosity of the suspension.

Immersed boundary-lattice Boltzmann method
Rheology
Shear reversal
Suspensions
Time-varying shear

http://resolver.tudelft.nl/uuid:91fdefb8-01de-4775-8b05-124d88f45fb1

https://doi.org/10.1016/j.compfluid.2021.105115

0045-7930

Computers & Fluids, 230

Institutional Repository

journal article

© 2021 Sudharsan Srinivasan, H.E.A. van den Akker, Orest Shardt