Yang, QQYangWillis, APAPWillisHwang, YYHwang2017-10-022018-05-172017-11-17Journal of Fluid Mechanics, 2017, 834, pp.531-5540022-1120http://hdl.handle.net/10044/1/51436Several recent studies have reported that there exists a self-similar form of invariant solutions down to the Kolmogorov microscale in the bulk region of turbulent Couette flow. While their role in a fully developed turbulent flow is yet to be identified, here we report that there exists a related mechanism of turbulence production at the Kolmogorov microscale in the bulk region of turbulent Couette flow by performing a set of minimal-span direct numerical simulations up to friction Reynolds number . This mechanism is found to essentially originate from the non-zero mean shear in the bulk region of the Couette flow, and involves eddy turn-over dynamics remarkably similar to the so-called self-sustaining process (SSP) and/or vortex–wave interaction (VWI). A numerical experiment that removes all other motions except in the core region is also performed, which demonstrates that the eddies at a given wall-normal location in the bulk region are sustained in the absence of other motions at different wall-normal locations. It is proposed that the self-sustaining eddies at the Kolmogorov microscale correspond to those in uniform shear turbulence at transitional Reynolds numbers, and a quantitative comparison between the eddies in uniform shear and near-wall turbulence is subsequently made. Finally, it is shown that turbulence production by the self-sustaining eddies at the Kolmogorov microscale is much smaller than that of full-scale simulations, and that the difference between the two increases with Reynolds number.The final publication is available via Cambridge Journals Online at http://dx.doi.org/10.1017/jfm.2017.704Science & TechnologyTechnologyPhysical SciencesMechanicsPhysics, Fluids & PlasmasPhysicsturbulence simulationturbulence theoryturbulent flowsNEAR-WALL TURBULENCEDIRECT NUMERICAL-SIMULATIONEXACT COHERENT STRUCTURESHIGH REYNOLDS-NUMBERCHANNEL FLOWPIPE-FLOWATTACHED EDDIESSHEAR FLOWSSTATE-SPACETRANSITION01 Mathematical Sciences09 EngineeringFluids & PlasmasJournal Articlehttps://www.dx.doi.org/10.1017/jfm.2017.704EP/N019342/1EP/N019342/1