Pulsed-jet propulsion of a squid-inspired swimmer at high Reynolds number

Luo, Yang; Xiao, Qing; Zhu, Qiang; Pan, Guang

doi:10.1063/5.0027992

Cited by 26 publications

(14 citation statements)

References 44 publications

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“…However, to further elucidate the underlying mechanisms of aquatic jet propulsion, we need robust data in a comparative framework and the development of model species that can provide access to quantifying body-fluid interactions both inside and outside of the body cavity. To allow for better comparative data, a combination of rapidly evolving new methods, such as computational fluid dynamics (Krieg and Mohseni, 2013;Hou et al, 2020;Luo et al, 2020), robotics (Marut et al, 2012;Giorgio-Serchi et al, 2016), in situ diveroperated PIV (Sutherland et al, 2014) and even genetic techniques that can eliminate pigmentation in opaque jetting species (Crawford et al, 2020), will be crucial for success.…”

Section: Discussionmentioning

confidence: 99%

Cool your jets: biological jet propulsion in marine invertebrates

Gemmell

Dabiri

Colin

et al. 2021

Journal of Experimental Biology

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Pulsatile jet propulsion is a common swimming mode used by a diverse array of aquatic taxa from chordates to cnidarians. This mode of locomotion has interested both biologists and engineers for over a century. A central issue to understanding the important features of jet-propelling animals is to determine how the animal interacts with the surrounding fluid. Much of our knowledge of aquatic jet propulsion has come from simple theoretical approximations of both propulsive and resistive forces. Although these models and basic kinematic measurements have contributed greatly, they alone cannot provide the detailed information needed for a comprehensive, mechanistic overview of how jet propulsion functions across multiple taxa, size scales and through development. However, more recently, novel experimental tools such as high-speed 2D and 3D particle image velocimetry have permitted detailed quantification of the fluid dynamics of aquatic jet propulsion. Here, we provide a comparative analysis of a variety of parameters such as efficiency, kinematics and jet parameters, and review how they can aid our understanding of the principles of aquatic jet propulsion. Research on disparate taxa allows comparison of the similarities and differences between them and contributes to a more robust understanding of aquatic jet propulsion.

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Section: Discussionmentioning

confidence: 99%

Cool your jets: biological jet propulsion in marine invertebrates

Gemmell

Dabiri

Colin

et al. 2021

Journal of Experimental Biology

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“…This compressible flow solver has been successfully validated and applied to various incompressible flow simulations involving boundary motion in our previous work (Liu et al, 2016;Luo et al, 2020a;Shi et al, 2020;Xiao and Liao, 2010). The validations include simulations of flow over a flexible cantilever behind a square cylinder, the bending of a flexible plate in the uniform flow, the response of a flexible plate in forced heave motion (Luo et al, 2020b), and flow over a NACA 0012 airfoil (Luo et al, 2020c).…”

Section: Mach Number May Become Larger Thanmentioning

confidence: 99%

Jet propulsion of a squid-inspired swimmer in the presence of background flow

2021

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Inspired by recent studies of a squid-like swimmer, we propose a three-dimensional jet propulsion system composed of an empty chamber enclosed within a deformable body with an opening. By prescribing the body deformation and jet velocity profile, we numerically investigate the jet flow field and propulsion performance under the influence of background flow during a single deflation procedure. Three jet velocity profiles, i.e., constant, cosine and half cosine, are considered. We find that the maximum circulation of the vortex ring is reduced at a higher background flow velocity. This is because stronger interaction between the jet flow and background flow makes it harder to feed the leading vortex ring. Regarding thrust production, our analysis based on conservation of momentum indicates that with the constant profile the peak thrust is dominated by the time derivative of the fluid momentum inside the body, while momentum flux related thrust accounts for the quasi-steady thrust. For the cosine profile, its peak is mainly sourced from momentum flux associated with the unsteady vortex ring formation. No prominent thrust peak exists with the half cosine profile whose thrust continuously increases during the jetting. For all the three jet velocity profiles, added-mass related thrust attributed to body deformation enhances the overall thrust generation nonnegligibly. Under the present tethered mode, the background flow has negligible influence on the thrust attributed to momentum flux and momentum change of the fluid inside the body.However, it indeed affects the over pressure-related thrust but its effect is relatively small. The overall thrust delines due to the significantly increased drag force at large incoming flow speed despite the rise of added-mass related thrust. Unsteady thrust involving vortex ring formation becomes more important in the overall thrust generation with an increased background flow velocity, reflected by larger ratios of the unsteady impulse to jet thrust impulse.

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“…p1 and p2) are convected further downstream (t5) and a new vortex pair p3 is shed again beyond the throat (t6). Such a fluid flow is different from the jet produced in a nozzle and shows some similarity to the jet propulsion of a cephalopod under water (Luo et al 2020).…”

Section: Effects Of Mmentioning

confidence: 89%

Transition to chaos in a two-sided collapsible channel flow

et al. 2021

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The nonlinear dynamics of a two-sided collapsible channel flow is investigated by using an immersed boundary-lattice Boltzmann method. The stability of the hydrodynamic flow and collapsible channel walls is examined over a wide range of Reynolds numbers $Re$ , structure-to-fluid mass ratios $M$ and external pressures $P_e$ . Based on extensive simulations, we first characterise the chaotic behaviours of the collapsible channel flow and explore possible routes to chaos. We then explore the physical mechanisms responsible for the onset of self-excited oscillations. Nonlinear and rich dynamic behaviours of the collapsible system are discovered. Specifically, the system experiences a supercritical Hopf bifurcation leading to a period-1 limit cycle oscillation. The existence of chaotic behaviours of the collapsible channel walls is confirmed by a positive dominant Lyapunov exponent and a chaotic attractor in the velocity-displacement phase portrait of the mid-point of the collapsible channel wall. Chaos in the system can be reached via period-doubling and quasi-periodic bifurcations. It is also found that symmetry breaking is not a prerequisite for the onset of self-excited oscillations. However, symmetry breaking induced by mass ratio and external pressure may lead to a chaotic state. Unbalanced transmural pressure, wall inertia and shear layer instabilities in the vorticity waves contribute to the onset of self-excited oscillations of the collapsible system. The period-doubling, quasi-periodic and chaotic oscillations are closely associated with vortex pairing and merging of adjacent vortices, and interactions between the vortices on the upper and lower walls downstream of the throat.

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Pulsed-jet propulsion of a squid-inspired swimmer at high Reynolds number

Cited by 26 publications

References 44 publications

Cool your jets: biological jet propulsion in marine invertebrates

Cool your jets: biological jet propulsion in marine invertebrates

Jet propulsion of a squid-inspired swimmer in the presence of background flow

Transition to chaos in a two-sided collapsible channel flow

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