FLOW Highlight: Fully resolved simulations of fibers with a significant size in turbulent flows

The interaction between fibers and carrier fluid is modeled through an external boundary force method.
In this project, the turbulent flow is modeled by an entropy lattice Boltzmann method. Direct contact and lubrication force models for fiber-fiber interactions and fiber-wall interaction are taken into account to allow for a full four-way interaction. The figure shows a visualisation of the fibers in a turbulent channel flow (Re_\tau=180) with the fibers shown as the yellow rods. Turbulent eddies are visualized by showing iso-surfaces of the second invariant of the velocity gradients, marking out regions of high vortical motion.
Do-Quang, M., Amberg, G., Brethouwer, G., Johansson, A. (2014) “Simulation of finite-size fibres in turbulent channel flow”, Physical Review E, 89, 013006 .