Extreme wall shear stress events in turbulent pipe flows: spatial characteristics of coherent motions
Byron Guerrero, Martin F Lambert, Rey C Chin
Journal of Fluid Mechanics | Cambridge University Press (CUP) | Published : 2020
This work presents a detailed analysis of the flow structures relevant to extreme wall shear stress events for turbulent pipe flow direct numerical simulation data at a friction Reynolds number Reτ≈1000 . The results reveal that extreme positive wall-friction events are located below an intense sweep (Q4) event originated from a strong quasi-streamwise vortex at the buffer region. This vortex transports high streamwise momentum from the overlap and the outer layers towards the wall, giving rise to a high-speed streak within the inner region. This vortical structure also relates to regions with extreme wall-normal velocity. Consequently, the conditional fields of turbulence production and vis..View full abstract
This work was supported with supercomputing resources provided by the Phoenix HPC service at the University of Adelaide. This research was also undertaken with the assistance of resources provided at the NCI NF through the Computational Merit Allocation Scheme supported by the Australian Government. The authors acknowledge the financial support of the Australian Research Council.