Tunable flow asymmetry and flow rectification with bio-inspired soft leaflets

Brandenbourger, Martin; Dangremont, A.; Sprik, R.; Coulais, Corentin

doi:10.1103/physrevfluids.5.084102

Cited by 8 publications

(6 citation statements)

References 29 publications

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“…Natural fluidic systems, however, may hold clues to efficient control mechanisms. For instance, it is well established that animals are highly adapted to operate with time-varying flows [12][13][14], using, e.g., one-way valves to ensure a constant flow direction [3,15] and compliant tubing to smooth the flow [16]. However, since these elements often operate in a hierarchical vascular network [17], in some cases comprising approximately 10 7 channels [18], replicating their functionality in a synthetic device is not without difficulty.…”

Section: Introductionmentioning

confidence: 99%

Smoothing Oscillatory Peristaltic Pump Flow with Bioinspired Passive Components

et al. 2022

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Pulsating flows are common in many industrial, scientific, and natural fluidic systems. However, because the oscillatory flow component disturbs, e.g., optical measurements, deposition, or industrial processes, it is rarely desired. Moreover, in physiological conditions, pulsation control is desired. We explore the effect of using a plant-inspired nonlinear resistor to smooth the output of a peristaltic pump. Incorporating a 3D printed millifluidic biomimetic device reduces the oscillation amplitudes by 3 orders of magnitude, from 100% to 0.1% of the output flow rate. This represents a tenfold improvement relative to a purely linear resistive-capacitive approach. The observed flow kinetics compare well to a predictive model of peristaltic transport, allowing the further development of optimized fluid-handling systems driven by pulsatile flow. Applications to particle tracking and jetting are considered.

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Section: Introductionmentioning

confidence: 99%

Smoothing Oscillatory Peristaltic Pump Flow with Bioinspired Passive Components

et al. 2022

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“…While focus will be given to this lymphatics-inspired model, the technique demonstrated in this paper could be used for a variety of problems containing a dense array of nonlinear elements satisfying (1.1), and could be of potential interest for engineering applications that incorporate artificial valves (see e.g. Park et al 2018;Brandenbourger et al 2020). The key observation will be that, when (1.1) is satisfied, the precise placement of valves becomes unimportant, and the flow is well approximated by treating the entire medium as a fluid with nonlinear properties inherited from the valves.…”

Section: Introductionmentioning

confidence: 99%

Operating principles of peristaltic pumping through a dense array of valves

Winn,

Katifori

2024

J. Fluid Mech.

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Immersed nonlinear elements are prevalent in biological systems that require a preferential flow direction, such as the venous and the lymphatic system. We investigate here a certain class of models where the fluid is driven by peristaltic pumping and the nonlinear elements are ideal valves that completely suppress backflow. This highly nonlinear system produces discontinuous solutions that are difficult to study. We show that, as the density of valves increases, the pressure and flow are well approximated by a continuum of valves which can be analytically treated, and we demonstrate through numeric simulation that the approximation works well even for intermediate valve densities. We find that the induced flow is linear in the peristaltic amplitude for small peristaltic forces and, in the case of sinusoidal peristalsis, is independent of pumping direction. Despite the continuum approximation used, the physical valve density is accounted for by modifying the resistance of the fluid appropriately. The suppression of backflow causes a net benefit in adding valves when the valve density is low, but once the density is high enough, valves predominately suppress forward flow, suggesting there is an optimum number of valves per wavelength. The continuum model for peristaltic pumping through an array of valves presented in this work can eventually provide insights about the design and operating principles of complex flow networks with a broad class of nonlinear elements.

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“…They are more adaptable and resilient to fluctuating environments, and their ability to shape-shift makes them more versatile. Among other applications are the implementation of soft valves that autonomously regulate the flow rate through the deformation of flaps [8,9], or enhanced propulsion by flexible wings and propellers [10][11][12]. In all those situations, gaining passive control over the deformation is a powerful means of regulating the fluid loading on the structure.…”

Section: Introductionmentioning

confidence: 99%

Shape reconfiguration through origami folding sets an upper limit on drag

2022

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Mechanisms of drag reduction through shape reconfiguration have been extensively studied on model geometries of plates and beams that deform primarily in bending. Adding an origami crease pattern to such plates produces a distinct class of deformation modes, with large shape changes along selected degrees of freedom. Here, we investigate the impact of those creases on reconfiguration processes and on drag, focusing on the waterbomb base as a generic case. When placed in a uniform airflow, this origami unit folds into a compact structure, whose frontal area collapses with increasing flow velocity. It enhances drag reduction to the point that fluid loading eventually ceases to increase with flow speed, reaching an upper limit. We further show that this limit is adjustable through the origami structural parameters: the stiffness and rest angle of the folds, and their pattern. Experimental results, corroborated by a fluid–elastic theoretical model, point to a scenario consistent with the previous literature: reconfiguration is governed by a dimensionless Cauchy number that measures the competition between fluid loading and elastic resistance to deformation, here embodied in creases. This foldable system yet stands out through the rare passive drag-capping lever it provides, a valuable asset for self-protection in strong wind.

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Tunable flow asymmetry and flow rectification with bio-inspired soft leaflets

Cited by 8 publications

References 29 publications

Smoothing Oscillatory Peristaltic Pump Flow with Bioinspired Passive Components

Smoothing Oscillatory Peristaltic Pump Flow with Bioinspired Passive Components

Operating principles of peristaltic pumping through a dense array of valves

Shape reconfiguration through origami folding sets an upper limit on drag

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