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Challita EJ, Rohilla P, Bhamla MS. Fluid Ejections in Nature. Annu Rev Chem Biomol Eng 2024; 15:187-217. [PMID: 38669514 PMCID: PMC11269045 DOI: 10.1146/annurev-chembioeng-100722-113148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2024]
Abstract
From microscopic fungi to colossal whales, fluid ejections are universal and intricate phenomena in biology, serving vital functions such as animal excretion, venom spraying, prey hunting, spore dispersal, and plant guttation. This review delves into the complex fluid physics of ejections across various scales, exploring both muscle-powered active systems and passive mechanisms driven by gravity or osmosis. It introduces a framework using dimensionless numbers to delineate transitions from dripping to jetting and elucidate the governing forces. Highlighting the understudied area of complex fluid ejections, this review not only rationalizes the biophysics involved but also uncovers potential engineering applications in soft robotics, additive manufacturing, and drug delivery. By bridging biomechanics, the physics of living systems, and fluid dynamics, this review offers valuable insights into the diverse world of fluid ejections and paves the way for future bioinspired research across the spectrum of life.
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Affiliation(s)
- Elio J Challita
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA;
| | - Pankaj Rohilla
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA;
| | - M Saad Bhamla
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA;
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2
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Zhu Q. Locomotion performance of an axisymmetric 'flapping fin'. BIOINSPIRATION & BIOMIMETICS 2023; 18:066012. [PMID: 37774714 DOI: 10.1088/1748-3190/acfeb9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 09/29/2023] [Indexed: 10/01/2023]
Abstract
Inspired by the jet-propulsion mechanism of aquatic creatures such as sea salps, a novel locomotion system based on an axisymmetric body design is proposed. This system consists of an empty tube with two ends open. When the diameters of the front and back openings are changed periodically, the forward-backward symmetry is broken so that the system starts swimming. Viewed within a cross section, this system resembles a two-dimensional flapping fin with its leading edge located at the front opening and the trailing edge at the back opening. The feasibility of this system has been proven via numerical simulations using a fluid-structure interaction model based on the immersed-boundary framework. According to the results, at relatively low Reynolds number (O(102)), this simple locomotion method can easily achieve a mean swimming speed of 2 to 3 body lengths per deformation period. Further simulations illustrate the following characteristics: (1) within the chamber, the hydrodynamic interactions among different parts of the body leads to a performance-enhancing mechanism similar to the ground effect; (2) reducing the diameter of the body can strengthen this effect so that both the swimming speed and the energy efficiency are improved; (3) for better performance the amplitude of diameter oscillation at the trailing edge should be larger or at least equal to the one at the leading edge.
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Affiliation(s)
- Qiang Zhu
- Department of Structural Engineering, University of California, San Diego, La Jolla, CA 92093, United States of America
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3
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Zhu Q. Wall effect on the start maneuver of a jet swimmer. BIOINSPIRATION & BIOMIMETICS 2023; 18:036003. [PMID: 36889000 DOI: 10.1088/1748-3190/acc293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 03/08/2023] [Indexed: 06/18/2023]
Abstract
Inspired by aquatic creatures such as squid, the novel propulsion method based on pulsed jetting is a promising way to achieve high speed and high maneuverability. To study the potential application of this locomotion method in confined space with complicated boundary conditions, it is critical to understand their dynamics in the vicinity of solid boundaries. In this study we numerically examine the start maneuver of an idealized jet swimmer near a wall. Our simulations illustrate three important mechanisms: (1) due to the blocking effect of the wall the pressure inside the body is affected so that the forward acceleration is increased during deflation and decreased during inflation; (2) the wall affects the internal flow so that the momentum flux at the nozzle and subsequently the thrust generation during the jetting phase are slightly increased; (3) the wall affects the wake so that the refilling phase is influenced, leading to a scenario in which part of the energy expended during jetting is recovered during refilling to increase forward acceleration and reduce power expenditure. In general, the second mechanism is weaker than the other two. The exact effects of these mechanisms depend on physical parameters such as the initial phase of the body deformation, the distance between the swimming body and the wall, and the Reynolds number.
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Affiliation(s)
- Qiang Zhu
- Department of Structural Engineering, University of California, San Diego, La Jolla, CA 92093, United States of America
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4
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Zhu Q, Xiao Q. Physics and applications of squid-inspired jetting. BIOINSPIRATION & BIOMIMETICS 2022; 17:041001. [PMID: 35512671 DOI: 10.1088/1748-3190/ac6d37] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Accepted: 05/05/2022] [Indexed: 06/14/2023]
Abstract
In the aquatic world jet propulsion is a highly successful locomotion method utilized by a variety of species. Among them cephalopods such as squids excel in their ability for high-speed swimming. This mechanism inspires the development of underwater locomotion techniques which are particularly useful in soft-bodied robots. In this overview we summarize existing studies on this topic, ranging from investigations on the underlying physics to the creation of mechanical systems utilizing this locomotion mode. Research directions that worth future investigation are also discussed.
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Affiliation(s)
- Qiang Zhu
- Department of Structural Engineering, University of California, San Diego, La Jolla, CA 92093, United States of America
| | - Qing Xiao
- Department of Naval Architecture, Ocean and Marine Engineering, University of Strathclyde, Glasgow, G4 0LZ, United Kingdom
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5
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The fish ability to accelerate and suddenly turn in fast maneuvers. Sci Rep 2022; 12:4946. [PMID: 35322112 PMCID: PMC8943085 DOI: 10.1038/s41598-022-08923-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 03/15/2022] [Indexed: 11/13/2022] Open
Abstract
Velocity burst and quick turning are performed by fish during fast maneuvers which might be essential to their survival along pray–predator encounters. The parameters to evaluate these truly unsteady motions are totally different from the ones for cruising gaits since a very large acceleration, up to several times the gravity, and an extreme turning capability, in less than one body length, are now the primary requests. Such impressive performances, still poorly understood, are not common to other living beings and are clearly related to the interaction with the aquatic environment. Hence, we focus our attention on the water set in motion by the body, giving rise to the relevant added mass and the associated phenomena in transient conditions, which may unveil the secret of the great maneuverability observed in nature. Many previous studies were almost exclusively concentrated on the vortical wake, whose account, certainly dominant at steady state, is not sufficient to explain the entangled transient phenomena. A simple two-dimensional impulse model with concentrated vorticity is used for the self-propulsion of a deformable body in an unbounded fluid domain, to single out the potential and the vortical impulses and to highlight their interplay induced by recoil motions.
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6
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Mohanty S, Paul A, Matos PM, Zhang J, Sikorski J, Misra S. CeFlowBot: A Biomimetic Flow-Driven Microrobot that Navigates under Magneto-Acoustic Fields. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2105829. [PMID: 34889051 DOI: 10.1002/smll.202105829] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 11/19/2021] [Indexed: 06/13/2023]
Abstract
Aquatic organisms within the Cephalopoda family (e.g., octopuses, squids, cuttlefish) exist that draw the surrounding fluid inside their bodies and expel it in a single jet thrust to swim forward. Like cephalopods, several acoustically powered microsystems share a similar process of fluid expulsion which makes them useful as microfluidic pumps in lab-on-a-chip devices. Herein, an array of acoustically resonant bubbles are employed to mimic this pumping phenomenon inside an untethered microrobot called CeFlowBot. CeFlowBot contains an array of vibrating bubbles that pump fluid through its inner body thereby boosting its propulsion. CeFlowBots are later functionalized with magnetic layers and steered under combined influence of magnetic and acoustic fields. Moreover, acoustic power modulation of CeFlowBots is used to grasp nearby objects and release it in the surrounding workspace. The ability of CeFlowBots to navigate remote environments under magneto-acoustic fields and perform targeted manipulation makes such microrobots useful for clinical applications such as targeted drug delivery. Lastly, an ultrasound imaging system is employed to visualize the motion of CeFlowBots which provides means to deploy such microrobots in hard-to-reach environments inaccessible to optical cameras.
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Affiliation(s)
- Sumit Mohanty
- Surgical Robotics Laboratory, Department of Biomechanical Engineering, University of Twente, Enschede, NB, 7522, The Netherlands
| | - Aniruddha Paul
- Surgical Robotics Laboratory, Department of Biomechanical Engineering, University of Twente, Enschede, NB, 7522, The Netherlands
- School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, SE-100 44, Sweden
| | - Pedro M Matos
- Surgical Robotics Laboratory, Department of Biomechanical Engineering, University of Twente, Enschede, NB, 7522, The Netherlands
| | - Jiena Zhang
- Vascularization Lab, Department of Biomechanical Engineering, University of Twente, Enschede, NB, 7522, The Netherlands
| | - Jakub Sikorski
- Surgical Robotics Laboratory, Department of Biomechanical Engineering, University of Twente, Enschede, NB, 7522, The Netherlands
| | - Sarthak Misra
- Surgical Robotics Laboratory, Department of Biomechanical Engineering, University of Twente, Enschede, NB, 7522, The Netherlands
- Surgical Robotics Laboratory, Department of Biomedical Engineering, University of Groningen and University Medical Center Groningen, Groningen, AV 9713, The Netherlands
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7
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Bi X, Zhu Q. Free swimming of a squid-inspired axisymmetric system through jet propulsion. BIOINSPIRATION & BIOMIMETICS 2021; 16:066023. [PMID: 34654001 DOI: 10.1088/1748-3190/ac3061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 10/15/2021] [Indexed: 06/13/2023]
Abstract
An axisymmetric fluid-structure interaction model based on the immersed-boundary approach is developed to study the self-propelled locomotion of a squid-inspired swimmer in relatively low Reynolds numbers (O(102)). Through cyclic deformation, the swimmer generates intermittent jet flow, which, together with the added-mass effect associated with the body deformation, provides thrust. Through a control volume analysis we are able to determine the jet-related thrust. By adding it to the added-mass-related thrust we separate the net thrust on the body from the drag effect due to forward motion, so that the propulsion efficiency in free swimming is found. This numerical algorithm and thrust-drag decomposition method are used to study the dynamics of the bio-inspired locomotion system in different conditions, whereby the performance is characterized by the aforementioned propulsion efficiency as well as the conventionally defined cost of transport.
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Affiliation(s)
- Xiaobo Bi
- Department of Structural Engineering, University of California, San Diego, La Jolla, CA 92093, United States of America
| | - Qiang Zhu
- Department of Structural Engineering, University of California, San Diego, La Jolla, CA 92093, United States of America
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8
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Yang Z, Chen D, Levine DJ, Sung C. Origami-Inspired Robot That Swims via Jet Propulsion. IEEE Robot Autom Lett 2021. [DOI: 10.1109/lra.2021.3097757] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Bujard T, Giorgio-Serchi F, Weymouth GD. A resonant squid-inspired robot unlocks biological propulsive efficiency. Sci Robot 2021; 6:6/50/eabd2971. [PMID: 34043579 DOI: 10.1126/scirobotics.abd2971] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 12/23/2020] [Indexed: 11/03/2022]
Abstract
Elasticity has been linked to the remarkable propulsive efficiency of pulse-jet animals such as the squid and jellyfish, but reports that quantify the underlying dynamics or demonstrate its application in robotic systems are rare. This work identifies the pulse-jet propulsion mode used by these animals as a coupled mass-spring-mass oscillator, enabling the design of a flexible self-propelled robot. We use this system to experimentally demonstrate that resonance greatly benefits pulse-jet swimming speed and efficiency, and the robot's optimal cost of transport is found to match that of the most efficient biological swimmers in nature, such as the jellyfish Aurelia aurita The robot also exhibits a preferred Strouhal number for efficient swimming, thereby bridging the gap between pulse-jet propulsion and established findings in efficient fish swimming. Extensions of the current robotic framework to larger amplitude oscillations could combine resonance effects with optimal vortex formation to further increase propulsive performance and potentially outperform biological swimmers altogether.
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Affiliation(s)
- Thierry Bujard
- Engineering and Physical Sciences, University of Southampton, Southampton, UK
| | - Francesco Giorgio-Serchi
- Engineering and Physical Sciences, University of Southampton, Southampton, UK.,School of Engineering, University of Edinburgh, Edinburgh, UK
| | - Gabriel D Weymouth
- Engineering and Physical Sciences, University of Southampton, Southampton, UK. .,Data-Centric Engineering Programme, Alan Turing Institute, London, UK
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11
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Aracri S, Giorgio-Serchi F, Suaria G, Sayed ME, Nemitz MP, Mahon S, Stokes AA. Soft Robots for Ocean Exploration and Offshore Operations: A Perspective. Soft Robot 2021; 8:625-639. [PMID: 33450174 PMCID: PMC8713554 DOI: 10.1089/soro.2020.0011] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The ocean and human activities related to the sea are under increasing pressure
due to climate change, widespread pollution, and growth of the offshore energy
sector. Data, in under-sampled regions of the ocean and in the offshore patches
where the industrial expansion is taking place, are fundamental to manage
successfully a sustainable development and to mitigate climate change. Existing
technology cannot cope with the vast and harsh environments that need monitoring
and sampling the most. The limiting factors are, among others, the spatial
scales of the physical domain, the high pressure, and the strong hydrodynamic
perturbations, which require vehicles with a combination of persistent autonomy,
augmented efficiency, extreme robustness, and advanced control. In light of the
most recent developments in soft robotics technologies, we propose that the use
of soft robots may aid in addressing the challenges posed by abyssal and
wave-dominated environments. Nevertheless, soft robots also allow for fast and
low-cost manufacturing, presenting a new potential problem: marine pollution
from ubiquitous soft sampling devices. In this study, the technological and
scientific gaps are widely discussed, as they represent the driving factors for
the development of soft robotics. Offshore industry supports increasing energy
demand and the employment of robots on marine assets is growing. Such expansion
needs to be sustained by the knowledge of the oceanic environment, where large
remote areas are yet to be explored and adequately sampled. We offer our
perspective on the development of sustainable soft systems, indicating the
characteristics of the existing soft robots that promote underwater
maneuverability, locomotion, and sampling. This perspective encourages an
interdisciplinary approach to the design of aquatic soft robots and invites a
discussion about the industrial and oceanographic needs that call for their
application.
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Affiliation(s)
- Simona Aracri
- Scottish Microelectronics Centre, Institute for Integrated Micro and Nano Systems, School of Engineering, The University of Edinburgh, Edinburgh, United Kingdom
| | - Francesco Giorgio-Serchi
- Scottish Microelectronics Centre, Institute for Integrated Micro and Nano Systems, School of Engineering, The University of Edinburgh, Edinburgh, United Kingdom
| | - Giuseppe Suaria
- Institute of Marine Sciences-National Research Council (ISMAR-CNR), La Spezia, Italy
| | - Mohammed E Sayed
- Scottish Microelectronics Centre, Institute for Integrated Micro and Nano Systems, School of Engineering, The University of Edinburgh, Edinburgh, United Kingdom
| | - Markus P Nemitz
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA.,Robotics Engineering Program, Department of Mechanical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Stephen Mahon
- Scottish Microelectronics Centre, Institute for Integrated Micro and Nano Systems, School of Engineering, The University of Edinburgh, Edinburgh, United Kingdom
| | - Adam A Stokes
- Scottish Microelectronics Centre, Institute for Integrated Micro and Nano Systems, School of Engineering, The University of Edinburgh, Edinburgh, United Kingdom
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12
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Christianson CM, Cui Y, Ishida M, Bi X, Zhu Q, Pawlak G, Tolley MT. Cephalopod-inspired robot capable of cyclic jet propulsion through shape change. BIOINSPIRATION & BIOMIMETICS 2020; 16:016014. [PMID: 32992299 DOI: 10.1088/1748-3190/abbc72] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The compliance and conformability of soft robots provide inherent advantages when working around delicate objects or in unstructured environments. However, rapid locomotion in soft robotics is challenging due to the slow propagation of motion in compliant structures, particularly underwater. Cephalopods overcome this challenge using jet propulsion and the added mass effect to achieve rapid, efficient propulsion underwater without a skeleton. Taking inspiration from cephalopods, here we present an underwater robot with a compliant body that can achieve repeatable jet propulsion by changing its internal volume and cross-sectional area to take advantage of jet propulsion as well as the added mass effect. The robot achieves a maximum average thrust of 0.19 N and maximum average and peak swimming speeds of 18.4 cm/s (0.54 body lengths/s) and 32.1 cm/s (0.94 BL/s), respectively. We also demonstrate the use of an onboard camera as a sensor for ocean discovery and environmental monitoring applications.
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Affiliation(s)
| | - Yi Cui
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, UNITED STATES
| | - Michael Ishida
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, UNITED STATES
| | - Xiaobo Bi
- Department of Structural Engineering, University of California San Diego, La Jolla, California, UNITED STATES
| | - Qiang Zhu
- Department of Structural Engineering, University of California San Diego, La Jolla, California, UNITED STATES
| | - Geno Pawlak
- Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, UNITED STATES
| | - Michael T Tolley
- University of California San Diego, La Jolla, California, 92093, UNITED STATES
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Hou TG, Yang XB, Wang TM, Liang JH, Li SW, Fan YB. Locomotor transition: how squid jet from water to air. BIOINSPIRATION & BIOMIMETICS 2020; 15:036014. [PMID: 32079775 DOI: 10.1088/1748-3190/ab784b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The amazing multi-modal locomotion of flying squid helps to achieve fast-speed migration and predator-escape behavior. Observation of flying squid has been rarely reported in recent years, since it is challenging to clearly record the flying squid's aquatic-aerial locomotion in a marine environment. The existing reports of squid-flying events are rare and merely record the in-air motion. Therefore, the water-air locomotor transition of flying squid is still unknown. This paper proposes the idea of using CFD to simulate the process of the flying squid (Sthenoteuthis oualaniensis (S. oualaniensis)) launching from water into air. The results for the first time reveal the flow field information of squid in launching phase and show the kinematic parameters of flying squid in quantification. Both a trailing jet and pinch-off vortex rings are formed to generate launching thrust, and the formation number L ω /D ω is 5.22, demonstrating that the jet strategy is to produce greater time-averaged thrust rather than higher propulsion efficiency. The results also indicate that the maximum flying speed negatively correlates with the launch angle, indicating that a lower launch angle could result in a larger flying speed for the flying squid to escape. These findings explore the multi-modal locomotion of flying squid from a new perspective, helping to explain the trade-off strategy of water-to-air transition, and further enhance the performance of aquatic-aerial vehicles.
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Affiliation(s)
- T G Hou
- School of Mechanical Engineering and Automation, Beihang University, Beijing 100083, People's Republic of China. Shenyuan Honors College, Beihang University, Beijing 100083, People's Republic of China
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14
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Bi X, Zhu Q. Dynamics of a squid-inspired swimmer in free swimming. BIOINSPIRATION & BIOMIMETICS 2019; 15:016005. [PMID: 31726438 DOI: 10.1088/1748-3190/ab57e4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The untethered swimming performance of a two-dimensional squid-inspired swimmer is studied. Our model includes fully-coupled fluid-structure interaction and an idealized activation algorithm that drives periodic shape change of the body. We present results of both escape jetting via a single deflation-coasting motion and long-distance swimming via repeated inflation-deflation cycles. In both cases added-mass-related force is found to contribute significantly to thrust generation. Moreover, we find that the increase of the jet speed and oscillation frequency leads to higher swimming velocity. This, however, is achieved at the cost of reduced propulsion efficiency (i.e. higher cost of transport). During long-distance swimming, the system experiences three successive stages, acceleration, steady-state swimming, and off-track swimming caused by symmetry-breaking instability in the wake. Associated with these stages, three wake patterns are observed, nozzle-vortex-dominated wake, transit wake, and asymmetrical wake.
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Affiliation(s)
- Xiaobo Bi
- Department of Structural Engineering, University of California, San Diego, La Jolla, CA 92093, United States of America
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15
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16
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Bi X, Zhu Q. Numerical investigation of cephalopod-inspired locomotion with intermittent bursts. BIOINSPIRATION & BIOMIMETICS 2018; 13:056005. [PMID: 29972142 DOI: 10.1088/1748-3190/aad0ff] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Inspired by recent studies about the fluid dynamics of cephalopods in their escaping swimming mode, we propose a novel design of an underwater propulsion system using a deformable body with pressure chamber, which propels itself in burst-coast cycles through a combined effect of pulsed jet and added-mass related thrust. To investigate the performance of this system we create a free-swimming computational model-the body deformation is prescribed yet the forward motion is driven by hydrodynamic forces. Our focus is on a single bursting cycle, which corresponds to the case that the system rests between bursts. The results can also be applied to the starting stage of a continuous cruising motion. A numerical model using the boundary element method is developed to computationally study the swimming process and the dynamic characteristics of this system. The results show that in the bursting phase its peak speed depends on the size of the body, the deformation time, the amount of volume change during the deformation, and the size of the nozzle where the jet flow is generated. The optimal speed is found to coincide with the critical formation number, indicating that the formation of vortex rings in the wake plays a pivotal role in the dynamics of the system. The dynamics of the system in the coasting phase and the process of refilling the pressure chamber are also studied.
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Affiliation(s)
- Xiaobo Bi
- Department of Structural Engineering, University of California, San Diego, La Jolla, CA 92093, United States of America
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17
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Shen Z, Na J, Wang Z. A Biomimetic Underwater Soft Robot Inspired by Cephalopod Mollusc. IEEE Robot Autom Lett 2017. [DOI: 10.1109/lra.2017.2724760] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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18
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Giorgio-Serchi F, Arienti A, Corucci F, Giorelli M, Laschi C. Hybrid parameter identification of a multi-modal underwater soft robot. BIOINSPIRATION & BIOMIMETICS 2017; 12:025007. [PMID: 28140363 DOI: 10.1088/1748-3190/aa5ccc] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We introduce an octopus-inspired, underwater, soft-bodied robot capable of performing waterborne pulsed-jet propulsion and benthic legged-locomotion. This vehicle consists for as much as 80% of its volume of rubber-like materials so that structural flexibility is exploited as a key element during both modes of locomotion. The high bodily softness, the unconventional morphology and the non-stationary nature of its propulsion mechanisms require dynamic characterization of this robot to be dealt with by ad hoc techniques. We perform parameter identification by resorting to a hybrid optimization approach where the characterization of the dual ambulatory strategies of the robot is performed in a segregated fashion. A least squares-based method coupled with a genetic algorithm-based method is employed for the swimming and the crawling phases, respectively. The outcomes bring evidence that compartmentalized parameter identification represents a viable protocol for multi-modal vehicles characterization. However, the use of static thrust recordings as the input signal in the dynamic determination of shape-changing self-propelled vehicles is responsible for the critical underestimation of the quadratic drag coefficient.
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Affiliation(s)
- F Giorgio-Serchi
- Fluid Structure Interaction Research Group, University of Southampton, Southampton SO16 7QL, United Kingdom
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Underwater Soft Robotics, the Benefit of Body-Shape Variations in Aquatic Propulsion. SOFT ROBOTICS: TRENDS, APPLICATIONS AND CHALLENGES 2017. [DOI: 10.1007/978-3-319-46460-2_6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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20
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Giorgio-Serchi F, Arienti A, Laschi C. Underwater soft-bodied pulsed-jet thrusters: Actuator modeling and performance profiling. Int J Rob Res 2016. [DOI: 10.1177/0278364915622569] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A new kind of underwater vehicle is developed by taking inspiration from cephalopods. Its actuation routine is scrutinized via a suitable model. Similar to octopuses and squids, these vehicles consist of an elastic, hollow shell capable of undergoing sequential stages of ingestion and ejection of ambient fluid, which is driven by the recursive inflation and deflation of the shell. The shell actively collapses, and in this way it expels water through a funnel; then it passively returns to the inflated shape, drawing ambient fluid into the cavity. By doing so, a pulsed-jet propulsion routine is performed that enables the vehicle to propel itself in water. Due to their soft nature, the actuation of these vehicles is largely dependent on the subtle management of the elastic response of the shell throughout the propulsion routine. A kinematic model of the actuation mechanism, thoroughly corroborated by experimental validation, is devised which elucidates the relationship between the active (collapse) and passive (refill) stages of the actuation. Upon association with the dynamics of the vehicle, this model permits the derivation of the generic performance profiles of this new kind of vehicle. It is acknowledged that, for given design specifications, an optimal swimming speed exists in coincidence with the coordinated operation between the crank mechanism driving the shell contraction and the onset of elastic energy, which determines the speed of inflation of the shell. These results are invaluable in the definition of rigorous design criteria and derivation of ad-hoc control laws for a new breed of optimized soft-bodied, pulsed-jet, unmanned underwater vehicles.
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Affiliation(s)
- Francesco Giorgio-Serchi
- Southampton Marine and Maritime Institute, University of Southampton, UK
- Scuola Superiore Sant’Anna, The Biorobotics Institute, Italy
| | - Andrea Arienti
- Scuola Superiore Sant’Anna, The Biorobotics Institute, Italy
| | - Cecilia Laschi
- Scuola Superiore Sant’Anna, The Biorobotics Institute, Italy
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