Determination of groove shape with strong destabilization and low hydraulic drag

Yadav, Nikesh; Gepner, S. W.; Szumbarski, Jacek

doi:10.1016/j.ijheatfluidflow.2020.108751

Cited by 10 publications

(9 citation statements)

References 42 publications

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“…Results of this verification are outlined in the Appendix. We also note that the approach used here has already been established for similar flows (Gepner & Floryan 2016;Yadav et al 2017Yadav et al , 2018Hossain, Cantwell & Sherwin 2021;Yadav, Gepner & Szumbarski 2021) and both spatial and temporal resolutions used in this work are more than sufficient to recover both hydrodynamic stability and nonlinear saturation states, as outlined in Yadav et al (2017).…”

Section: Problem Descriptionmentioning

confidence: 92%

“…In the case of corrugated channel flow with only the Poiseuille forcing applied (Yadav et al. 2017, 2021) flow features formed in consequence of nonlinear saturation propagate downstream, along the direction that the applied pressure acts. In the case of the configuration, considered here, propagation direction might change as the Poiseuille component is decreased.…”

Section: Nonlinear Saturation Of the Unstable Modementioning

confidence: 99%

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Slowing down convective instabilities in corrugated Couette–Poiseuille flow

Yadav

Gepner²

2022

J. Fluid Mech.

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Couette–Poiseuille (CP) flow in the presence of longitudinal grooves is studied by means of numerical analysis. The flow is actuated by movement of the flat wall and pressure imposed in the opposite direction. The stationary wall features longitudinal grooves that modify the flow, change hydrodynamic drag on the driving wall and cause onset of hydrodynamic instability in the form of travelling waves with a consequent supercritical bifurcation, already at moderate ranges of the Reynolds number. We show that by manipulating this system it is possible to significantly decrease phase speed of the unstable wave and to effectively decouple time scales of wave propagation and amplification with a potential to significantly reduce the distance required for the onset of nonlinear effects. Current analysis begins with concise characterization of stationary, laminar CP flow and the effects of applying a selected corrugation pattern, followed by determination of conditions leading to the onset of instabilities. In the second part we illustrate selected nonlinear solutions obtained for low, supercritical values of the Reynolds numbers and due to the amplification of unstable travelling waves of possibly low phase velocities. This work is concluded with a short discussion of a linear evolution of a wave packet consisting of a superposition of a number of unstable waves and initiated by a localized pulse. This part illustrates that in addition to the reduction of the phase velocity of a single, unstable mode, imposition of the Couette component also reduces group velocity of a wave packet.

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Section: Problem Descriptionmentioning

confidence: 92%

Section: Nonlinear Saturation Of the Unstable Modementioning

confidence: 99%

Slowing down convective instabilities in corrugated Couette–Poiseuille flow

Yadav

Gepner²

2022

J. Fluid Mech.

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“…As shown in Figure , the cross‐section shapes of the simplified microgroove structure are triangular (or V‐shaped, sawtooth shape), trapezoidal, circular, rectangular (or riblets), wavy (or sinusoidal), etc. [ 42,43 ]…”

Section: Drag Reduction Microstructuresmentioning

confidence: 99%

“…As shown in Figure 3, the cross-section shapes of the simplified microgroove structure are triangular (or V-shaped, sawtooth shape), trapezoidal, circular, rectangular (or riblets), wavy (or sinusoidal), etc. [42,43] Some simplified cross-sectional shapes of the grooves are shown in Figure 3, where s, h, t, and a represent the groove spacing, height, groove spacing, and the angle of the tip, respectively. According to the shape and size of the different microstructures, the best drag reduction capability can be obtained under certain conditions (such as fluid medium and fluid velocity).…”

Section: Appearancementioning

confidence: 99%

Focus on Bioinspired Textured Surfaces toward Fluid Drag Reduction: Recent Progresses and Challenges

et al. 2021

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After a long period of biological evolution, natural creatures will inevitably evolve body surfaces suitable for the living environment. The functions of natural biological surfaces are abundant and powerful, including antiadhesion, self‐cleaning, drag reduction, anti‐icing, wear resistance, and other characteristics. In the context of coping with the energy crisis, inspired by natural biological surface microstructures, researchers explore biomimetic surface microstructures that reduce fluid drag and investigate the mechanisms of drag reduction. Herein, mainly the current state of research on biomimetic textured surfaces that can be applied to fluid drag reduction is reviewed and the microstructures’ morphology, drag reduction mechanisms, and the fabrication techniques of textured surfaces are discussed in detail. In particular, the experimental methods for measuring the drag reduction effect of textured surfaces are introduced, which is extremely rare. The article concludes with a summary of existing problems and future directions in the research of biomimetic surface drag reduction technology. This Review can provide a reference for practical application and laboratory research of drag reduction in marine transportation, military weapons, aviation, and pipeline systems.

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“…Various passive approaches have been proposed that may help reduce the resistance to motion. Included in these is the incorporation of surface grooves or corrugations for laminar (Mohammadi & Floryan 2013 a , b , 2014, 2015; Moradi & Floryan 2013; Yadav, Gepner & Szumbarski 2021) and turbulent (Walsh 1983; Chen et al. 2016; DeGroot, Wang & Floryan 2016) flows.…”

Section: Introductionmentioning

confidence: 99%

The role of vibrations for reducing the resistance in the relative movement of parallel plates

Floryan

Haq

2022

J. Fluid Mech.

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The effect of surface vibrations on the propulsion augmentation and resistance in the relative movement of parallel plates has been studied. The analysis was focused on monochromatic waves and laminar flows. The effectiveness of the vibrations was gauged by determining the external force required to maintain the movement of one of the plates at a prescribed velocity. It is shown that waves propagating upstream always increase the resistance but the flow response to waves propagating downstream is more intricate and is a function of the flow Reynolds number. In general, waves must be sufficiently fast to reduce the flow resistance. This leads to a natural division between slow and fast waves; a characterization that is helpful for flows at a sufficiently small Reynolds number Re. An increase in Re brings into play the complication of possible resonances with the natural flow frequencies. Resonances are not possible with waves faster than the plate velocity and these supercritical waves generally decrease the flow resistance. More complex flow responses can occur with slower (subcritical) waves which tend to increase the flow resistance. A complete elimination of the resistance is possible if the waves are of sufficiently short wavelength and travel quickly. This suggests that our mechanism has great potential in the development of propulsion augmentation systems. None of the waves produced net energy savings.

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Determination of groove shape with strong destabilization and low hydraulic drag

Cited by 10 publications

References 42 publications

Slowing down convective instabilities in corrugated Couette–Poiseuille flow

Slowing down convective instabilities in corrugated Couette–Poiseuille flow

Focus on Bioinspired Textured Surfaces toward Fluid Drag Reduction: Recent Progresses and Challenges

The role of vibrations for reducing the resistance in the relative movement of parallel plates

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