Animation of particle lift-off in turbulent open channel flow based on data from PR-DNS

The animation shows the particle motion and the coherent vortical structures in particle-resolved DNS simulations of turbulent open channel flow. Please refer to the accompanying manuscript for the configuration, numerical method and the parameter values: "Investigating the mechanism by which finite-size heavy particles are entrained in turbulent open channel flow over a smooth surface" by T. Bzikadze, M. Weyrauch and M. Uhlmann, (J. Phys.: Conf. Ser., 2026) - [DOI TO BE ADDED when available]. The movie features a temporal sequence of duration corresponding to approximately 20 bulk time units, starting just after inserting the particles into the flow. The visualization shows two different views of the same data, indicating the particles (colored in black when in contact with the wall and in pink when lifted off) as well as a vertical line to indicate their wall distance more clearly. The channel wall is colored with the local streamwise shear-stress, the color indicating its fluctuation around the global average on a colormap from blue to red. The white semi-transparent surfaces are defined by the second invariant of the velocity gradient tensor (Hunt et al., Proc. ... mehrSummer Prog. CTR, 1988) taking a value equal to five times its r.m.s. value. Note that for clarity the data is only shown for the lower half of the open channel domain, i.e. for the wall-normal distance 0<=y<=h/2, where 'h' is the channel depth.