Transient development mechanisms operating on streaky shear flows are believed necessary for sustaining near-wall turbulence. Of the three individual mechanisms current - Orr, buy Wood Ranger Power Shears shop Wood Ranger Power Shears manual electric power shears garden power shears raise-up and ‘push-over’ - Lozano-Duran et al. J. Fluid Mech. 914, A8, 2021) have just lately observed that each Orr and push-over have to be present to sustain turbulent fluctuations given streaky (streamwise-unbiased) base fields whereas lift-up does not. We present right here, using Kelvin’s model of unbounded fixed shear augmented by spanwise streaks, that it is because the push-over mechanism can act in live performance with a ‘spanwise’ Orr mechanism to produce much-enhanced transient progress. Rey) occasions. Our results therefore assist the view that whereas raise-up is believed central for the roll-to-streak regenerative process, it's Orr and push-over mechanisms that are both key for the streak-to-roll regenerative course of in near-wall turbulence. Efforts to understand wall-bounded turbulence have naturally focussed on the wall and the (coherent) structures which form there (Richardson, 1922). The consensus is that there's (at the very least) a near-wall sustaining cycle (Hamilton et al., 1995
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Transient Growth in Streaky Unbounded Shear Flow: a Symbiosis of Orr And Push over Mechanisms
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