Relevant bibliographies by topics / Water jets Underwater propulsion

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Academic literature on the topic 'Water jets Underwater propulsion'

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Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Water jets Underwater propulsion"

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Tang, Jia-Ning, Ning-Fei Wang, and Wei Shyy. "Flow structures of gaseous jets injected into water for underwater propulsion." Acta Mechanica Sinica 27, no. 4 (July 11, 2011): 461–72. http://dx.doi.org/10.1007/s10409-011-0474-4.

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Song, Zhuoyuan, Cameron Mazzola, Eric Schwartz, Ruirong Chen, Julian Finlaw, Mike Krieg, and Kamran Mohseni. "A Compact Autonomous Underwater Vehicle With Cephalopod-Inspired Propulsion." Marine Technology Society Journal 50, no. 5 (September 1, 2016): 88–101. http://dx.doi.org/10.4031/mtsj.50.5.9.

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AbstractIn this paper, a bioinspired, compact, cost-effective autonomous underwater vehicle system is presented. Designed to operate in a heterogeneous, multivehicle collaboration hierarchy, the presented vehicle design features 3D printing technology to enable fast fabrication with a complex internal structure. Similar to a previous vehicle prototype, this system generates propulsive forces by expelling unsteady, pulsed jets, inspired by the locomotion of cephalopods and jellyfish. The novel thrusters enable the vehicle to be fully actuated in horizontal plane motions, without sacrificing the low-forward-drag, slender vehicle profile. By successively ingesting water and expelling finite water jets, periodic actuation forces are generated at all possible vehicle velocities, eliminating the need for control surfaces used in many conventional underwater vehicle designs. A semiactive buoyancy control system, inspired by the nautilus, adjusts the vehicle depth by passively allowing water flowing into and actively expelling water out of an internal bladder. A compact embedded system is developed to achieve the control and sensing capabilities necessary for multiagent interactions with the minimum required processing power and at a low energy cost. The new vehicle design also showcases an underwater optical communication system for short-range, high-speed data transmission, supplementing the conventional acoustic communication system. Experimental results show that, with the thruster motors powered at a 60% duty-cycle, the new vehicle is able to achieve a 1/4 zero-radius turn in 3.5 s and one-body-width sway translation in 2.5 s.
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Krieg, Michael, Peter Klein, Robert Hodgkinson, and Kamran Mohseni. "A Hybrid Class Underwater Vehicle: Bioinspired Propulsion, Embedded System, and Acoustic Communication and Localization System." Marine Technology Society Journal 45, no. 4 (July 1, 2011): 153–64. http://dx.doi.org/10.4031/mtsj.45.4.11.

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AbstractInspired by the natural locomotion of jellyfish and squid, a series of compact thrusters series is developed for propulsion and maneuvering of underwater vehicles. These thrusters successively ingest and expel jets of water in a controlled manner at high frequencies to generate propulsive forces. The parameters controlling the performance of the thrusters are reviewed and investigated to achieve higher thrust levels. The thrusters are compact and can be placed completely inside a vehicle hull providing the desired maneuvering capability without sacrificing a sleek hydrodynamic shape for efficient cruising. The system design of a prototype hybrid vehicle, called CephaloBot, utilizing these thrusters, is also presented. A compact and custom-developed embedded system is also designed for the CephaloBot. Key features of the system include a base set of navigational sensors, an acoustic system for localization and underwater communication, Xbee RF transceiver for communication above water, and a LabVIEW programmed processing board.
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Shaari, Muhammad Farid, Samad Zahurin, Mohd Elmi Abu Bakar, and M. Mariatti. "Design Consideration of Bio-Inspired Contractible Water-Jet Propulsor for Mini Autonomous Underwater Robot." Advanced Materials Research 463-464 (February 2012): 1583–88. http://dx.doi.org/10.4028/www.scientific.net/amr.463-464.1583.

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The main aim of this paper is to discuss the general design considerations for contractible water-jet propulsion system for mini underwater robot locomotion. The motivation of this paper is the problems that occurred to the motorized turbine blade propeller for a lower than centimeter scale underwater robot. Contractile water-jet propulsion mechanism is proposed to counter the turbine blade problem. In this research, active materials had been proposed as the actuator for the contractile function. The integration of active material structure and passive structure caused significant consequence on the kinematic and dynamic of the robot. This including the dimension variation, stress distribution as well as contraction force which affects the hydrodynamic efficiency of the propulsion. Several essential design considerations were highlighted and discussed.
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Mo, Jixue, Zhihuai Miao, Bing Li, Yunlu Zhang, and Zhendong Song. "Design, analysis, and performance verification of a water jet thruster for amphibious jumping robot." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 15 (April 26, 2019): 5431–47. http://dx.doi.org/10.1177/0954406219844529.

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In nature, certain aquatic animals and seabirds are capable of leaping from water surface and overcoming aquatic obstacles with ease. Inspired by that, researchers have developed various underwater robots, which can perform the aquatic jumping motion. Although there are several ways to achieve it, the water jet propulsion is the most appropriate approach for the amphibious jumping robot, which is under development. In this paper, a high-performance water jet thruster powered by liquid nitrogen is proposed to be the potential actuator for the amphibious jumping robot. The theoretical jumping model is built to optimize the initial volume fraction of water inside thruster and analyze its parameters' variation during water jet. Then the computational fluid dynamics simulations by ANSYS FLUENT software are carried out to analyze the self-pressurization process of liquid nitrogen as well as the water jet process. Finally, the proof-of-concept outdoor experiments present that the 3.7 kg thruster's maximum aquatic and terrestrial jumping heights are 25.1 m and 24.4 m, respectively. A simple heat transfer analysis between water and liquid nitrogen is also conducted, and the order of magnitude estimation of heat transfer coefficient is given to be 265W/ (m2·K) based on the experimental reaction time.
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Han, Zhao Lin, and De Long Chen. "The Kinematic Analysis of Double Water Jets Ship." Applied Mechanics and Materials 723 (January 2015): 167–70. http://dx.doi.org/10.4028/www.scientific.net/amm.723.167.

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This document explains hydrodynamic force of water jet propulsion and kinematic characteristics of double water jets ship. Firstly, study on the water jet thrust based on the theorem of momentum. Then discuss the hydrodynamic performance of the water jet reversing bucket, calculate the backing force produced in the condition of different flow rate and nozzle angle. On the basis of hydrodynamic analysis of water jet, we next explore the various motion modes of double water jet propulsion ship, especially kinematic analysis of ship’s in-situ rotary movement and transverse movement.
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Moon, Heejang, Seongjoo Han, Youngjun You, and Minchan Kwon. "Hybrid Rocket Underwater Propulsion: A Preliminary Assessment." Aerospace 6, no. 3 (March 6, 2019): 28. http://dx.doi.org/10.3390/aerospace6030028.

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This paper presents an attempt to use the hybrid rocket for marine applications with a 500 N class hybrid motor. A 5-port high density polyethylene (HDPE) fuel grain was used as a test-bed for the preliminary assessment of the underwater boosting device. A rupture disc preset to burst at a given pressure was attached to the nozzle exit to prevent water intrusion where a careful hot-firing sequence was unconditionally required to avoid the wet environment within the chamber. The average thrust level around 450 N was delivered by both a ground test and an underwater test using a water-proof load cell. However, it was found that instantaneous underwater thrusts were prone to vibration, which was due in part to the wake structure downstream of the nozzle exit. Distinctive ignition curves depending on the rupture disc bursting pressure and oxidizer mass flow rate were also investigated. To assess the soft-start capability of the hybrid motor, the minimum power thrust, viewed as the idle test case, was evaluated by modulating the flow controlling valve. It was found that an optimum valve angle, delivering 16.3% of the full throttle test case, sustained the minimum thrust level. This preliminary study suggests that the throttable hybrid propulsion system can be a justifiable candidate for a short-duration, high-speed marine boosting system as an alternative to the solid underwater propulsion system.
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Xin, Ba, Luo Xiaohui, Shi Zhaocun, and Zhu Yuquan. "A vectored water jet propulsion method for autonomous underwater vehicles." Ocean Engineering 74 (December 2013): 133–40. http://dx.doi.org/10.1016/j.oceaneng.2013.10.003.

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SUZUKI, Akihiro, Masahiro OSAKABE, and Hayato KONDO. "Propulsion System of Underwater Vehicle with Low Speed Water Jet." Proceedings of the National Symposium on Power and Energy Systems 2016.21 (2016): A113. http://dx.doi.org/10.1299/jsmepes.2016.21.a113.

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Lu, Yeming, Haoran Liu, Xiaofang Wang, and Hui Wang. "Study of the Operating Characteristics for the High-Speed Water Jet Pump Installed on the Underwater Vehicle with Different Cruising Speeds." Journal of Marine Science and Engineering 9, no. 3 (March 22, 2021): 346. http://dx.doi.org/10.3390/jmse9030346.

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Due to the higher propulsive efficiency, lesser vibration, and better maneuverability, the water jet pump is widely applied to high-speed underwater vehicles. By taking a newly developed water jet pump system as the object, the corresponding underwater vehicle’s operating characteristics affected by different cruising speeds (15.43, 30.86, and 52.47 m/s) were investigated. The steady results reply that the cruising speed increase will result in the decline of the overall performances comprised of the head, the efficiency, the thrust, and the power. While, by using different analyzing methods, the unsteady results are listed as follows: (1) The energy loss theory denotes that the increasing cruising speed promoted the kinetic energy diffusion from the Reynolds stress and viscous stress and depress the turbulent kinetic energy production and the viscous dissipation. (2) The statistical PLS method reveals that the tip load effect on the leakage flow becomes weaker when the cruising speed becomes larger, while the effect from the scraping pressure has a completely opposite trend. (3) Further unsteady analysis implies that the increasing cruising speed makes the pressure pulsation larger and makes the radial force, the axial force, and the cloudy cavity size smaller.
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Dissertations / Theses on the topic "Water jets Underwater propulsion"

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Thornhill, Eric. "Development of waterjet testing techniques." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0029/MQ47483.pdf.

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Athanassiadis, Athanasios G. "Parallel pulsed jets for precise underwater propulsion." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/103430.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 95-98).
A significant limitation for underwater robots is their ability to maneuver in tight spaces or for complex tracking tasks. Next generation vehicles require thrusters that can overcome this problem and efficiently provide high maneuverability at low speeds. Recently, thruster design has begun to draw inspiration from nature's swimmers, applying the principles of pulsed jet propulsion to robotic thrusters. Although most developments have focused on single jet actuators, nature provides some indications that multi-jet systems can provide propulsive benefits -- marine invertebrates called sales connect into chains of individual animals that each eject short jets to collaboratively move the entire chain efficiently around the ocean. However, despite the promise of multi-jet propulsion, there are no existing models or empirical data that explain the physics of multi-jet propulsion. As a result, there are no physically motivated rules to guide the design of man-made multi-jet thrusters. In this thesis, I experimentally investigate how interactions between neighboring jets in a multi-jet thruster will affect the system's propulsive performance. I use high-speed fluorescence imaging to investigate the mutual influence of two pulsed jets under conditions relevant to low-speed maneuvering in a vehicle (Re ~ 350). Using a new force estimation technique developed in this thesis, I analyze the video data to evaluate how thrust and efficiency are affected by the jet spacing. This analysis reveals that, compared to non-interacting jets, the efficiency and thrust generated by the pair of interacting jets can fall by nearly 10% as the jets are brought into close proximity. Based on this data, I develop a model of vortex interactions to explain the thrust and efficiency drop. The data and model described in this thesis contribute new insights to understand vortex formation in pulsed jets, and these results can be used to guide the design of multi-jet underwater propulsion syste
by Athanasios G. Athanassiadis.
S.M.
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Ellis, Jeremy Conrad. "The Effect of Projectile Nose Shape on the Formation of the Water Entry Cavity." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6445.

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This research focuses on the effect of several convex and concave nose shapes on cavity formation for both hydrophilic and hydrophobic projectiles. It specifically investigates the effect of convex shape on the threshold velocity for cavity formation as well as the effect of concave shapes on cavity formation in terms of impact velocity, geometry of the concave shape and wettability of the projectile. For the convex cases, the streamlined axisymmetric shape significantly increases the threshold velocity when cavities form and is most pronounced for the ogive and cone. The study demonstrates that measuring the wetting angle and impact velocity is not enough to predict cavity behavior, rather the roughness and nose shape must also be taken into consideration for convex projectiles. For the concave cases, the cavities formed are highly influenced by impact speed and nose shape. Wetting angle did not have any visible effect on the cavity formed at higher impact speeds (7 m/s). The dynamics of the cavity formation are dominated by the pocket of trapped air formed when the concave projectiles impact the water. At low impact speeds (~0-1 m/s) the trapped air can separate the flow from the leading edge of the projectile nose when venting out and cause a large cavity to form, depending on the specific concave shape and speed. At moderate impact speeds (1-4 m/s) the trapped air will vent completely underwater forming a small ring-shaped cavity. At high impact speeds (4-10 m/s) the trapped pocket of air compresses tremendously and causes an unsteady pressure pulse, which can result in the formation of a bubble and jet in front of the cavity. The jet is formed by water passing behind the pocket of trapped air along the walls of the concave nose and converging into a jet at the top of the concave shape and entraining the trapped air as it descends.
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Gangadharan, Sathya Narayan. "Feasibility study of jet propulsion for remote operated underwater vehicles /." 1986. http://collections.mun.ca/u?/theses2,4018.

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Karnovsky, Hilton. "Production of free surface water jets using focused underwater shock waves." Thesis, 2014.

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It is possible to produce concentrated free surface water jets by rapidly accelerating a geometrically shaped curved deflector plate below the free water surface. This principle has been established using a self focusing electromagnetic acoustic source (FEMAS) and this report verifies it using a shock tube based mechanical analogue of that system. The shape, form and speed o f the water jets produced vary between the two systems. Discrete pressure measurements using a needle hydrophone positioned at different points below the free water surface are presented. The variation in pressure amplitudes recorded highlight the scatter and uncertainty inherent in a complex coupled system, while the form o f the pressure trace is dependant on the mechanical design o f the system in use and the position o f the needle hydrophone in the pressure field. To better understand the experimental system, a computer simulation using commercially availa ble non-linear dynamic analysis software has been developed. This shows that the water surface jets result from the overall hydrodynamic, flow initiated by rapid movement o f the deflector plate below the water surface.
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Nguyen, Anh-Tu, and 阮英琇. "Interaction between Underwater Explosion Bubbles with Associated Water Jets and Structures." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/96625081847777898720.

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博士
大葉大學
機械與自動化工程學系
102
Underwater explosion phenomenon is of interest of numerous researchers for various reasons, particularly in the area of military, because such phenomenon can cause serious damage to any nearby structure. Understanding this phenomenon helps improve the survivability of naval ships and submarines. After detonation, the shockwave radially propagates outwards and this is followed by a high-pressure bubble containing hot gaseous products of the explosion. The shockwave travels out through the water at high speed and can cause considerable damage on structures. Although the shockwave generates high-pressure load but its duration is very short, whereas pulsating bubble induces low-pressure load but it occurs for a substantially long time. Therefore, the oscillation of the bubble can result in global damage on structures. Furthermore, the formation of high-speed water jet during the bubble collapse can also cause local damage on nearby structures. Because an underwater explosion bubble phenomenon consists of a complicated sequence of events, the present study approached this phenomenon in two separated phases. In the first phase of the study, numerical models were introduced and verified by the experimental and theoretical data. Then, those models were applied for investigating the behavior of the bubble in the vicinity of different boundaries. In the second phase, the research focused on simulating the impact of a separated high-speed water jet on a flat plate. In which, the characteristics of impact pressure as well as the response of impacted structures were interpreted. To overcome the difficulties regarding the classical finite element method; such as large deformations, and flow simulation of fluid and gas, the Eulerian analysis in ABAQUS software was applied. This method allowed simulating multi-materials in an element, and the coupled Eulerian-Lagrangian technique helps solving the fluid-structure interaction (FSI), in which the Eluerian-Lagrangian contact contrains are enforced using penalty method. Despite of limitation relating to the simplifications such as laminar, incompressible viscous, and inviscid flow behaviors, as well as the idealization of explosion gas products, the comparison to experimental and empirical results shows that the numerical model enable to estimate the damage of structures due to the impact of water jet, and reliably reproduced crucial characteristics of the underwater explosion bubble, including the migration of the bubble, pressure pulse, and the formation of water jet in the bubble collapse. The results show that the wall has the effect of slow down the collapse rate of the bubble, the standoff distance factor and the stiffness factor affect the behavior of the bubble as well as the development of water jet in different ways. The highest impact pressure induced by water jet impact at the center of the impact area and the stagnation pressure scatters quite uniformly on the area of diameter of the jet head. The quantitative characterization of the UNDEX bubble model is suitable for other explosive charge types, masses, and depths.
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Valsaraj, Alokraj. "Application of boundary element methods (BEM) to internal propulsion systems; application to water-jets and inducers." Thesis, 2013. http://hdl.handle.net/2152/21495.

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A panel method derived from inviscid irrotational flow theory and utilizing hyperboloid panels is developed and applied to the simulation of steady fully wetted flows inside water-jet pumps and rocket engine inducers. The source and dipole influence coefficients of the hyperboloid panels are computed using Gauss quadrature. The present method solves the boundary value problem subject to a uniform inflow directly by discretizing the blade, casing/shroud and hub geometries with panels. The Green's integral equation and the influence coefficients for the water-jet/inducer problem are defined and solved by allocating constant strength sources and dipoles on the blade, hub and casing surfaces and constant strength dipoles on the shed wake sheets from the rotor/ stator blades. The rotor- stator interaction is accomplished using an iterative procedure which considers the effects between the rotor and the stator, via circumferentially averaged induced velocities. Finally, the hydrodynamic performance predictions for the water-jet pump and the inducer from the present method are validated against existing experimental data and numerical results from Reynolds Averaged Navier- Stokes (RANS) solvers.
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Murrin, David. "The evaluation of a waterjet system using computational fluid dynamics validated by wind tunnel tests /." 2002.

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Books on the topic "Water jets Underwater propulsion"

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Miller, Glenn A. Underwater sound radiation from single large raindrops at terminal velocity; the effects of asloped water surface at impact. Monterey, Calif: Naval Postgraduate School, 1992.

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Conference papers on the topic "Water jets Underwater propulsion"

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Tang, Jianing, Chien-Chou Tseng, Ningfei Wang, and Wei Shyy. "Flow Structures of Gaseous Jets Injected into Water for Underwater Propulsion." In 49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2011. http://dx.doi.org/10.2514/6.2011-185.

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Krieg, Michael, and Kamran Mohseni. "Thrust Enhancement From Radial Velocity in Squid Inspired Thrusters." In ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/omae2012-83976.

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Squid and jellyfish generate propulsive forces by successively taking in and expelling high momentum jets of water. This method of propulsion offers several advantages to underwater vehicles/robots. The driving mechanism can be placed internal to the vehicle, reducing the drag associated with an abundance of external thrusters and control surfaces. The thrusters can generate accurate predictable forcing in the low thrust range, while still generating thrust nearly instantaneously over the entire force range. Vortex ring formation dynamics play an important role in creating thrust. It is observed that squid and jellyfish eject fluid jets which are not exactly parallel, and have a contracting velocity in the radial direction. A prototype thruster was developed which generates both parallel and converging propulsive jets. The total impulse of the jet is determined from DPIV techniques to determine the effect a non-zero radial velocity had on thrust production. The radial velocity was observed to increase the total impulse of the jet by 70% for low stroke ratio jets, and 75% for large stroke ratio jets.
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Guo, Shuxiang, Juan Du, Xiufen Ye, Rui Yan, and Hongtao Gao. "The computational design of a water jet propulsion spherical underwater vehicle." In 2011 IEEE International Conference on Mechatronics and Automation (ICMA). IEEE, 2011. http://dx.doi.org/10.1109/icma.2011.5986358.

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Yue, Chunfeng, Shuxiang Guo, Xichuan Lin, and Juan Du. "Analysis and improvement of the water-jet propulsion system of a spherical underwater robot." In 2012 IEEE International Conference on Mechatronics and Automation (ICMA). IEEE, 2012. http://dx.doi.org/10.1109/icma.2012.6285686.

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Ananthakrishnan, Palaniswamy. "Hydrodynamic Analysis of Flapping Foils for Propulsion of Shallow-Water and Near-Surface Underwater Vehicles." In ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-24415.

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Hydrodynamic performance of flapping foils for the propulsion or station keeping of near-surface underwater vehicles is examined numerically. The objective of the project is to determine effects of momentum fluxes associated with the vortex wake, radiating waves and their interactions on the thrust and efficiency of the flapping foils. The fully nonlinear viscous flow problem is solved using a finite difference method based on boundary-fitted coordinates. Various flapping foil mechanisms, such as of a single foil, twin foil and hinge-connected double foil, are considered. Results are obtained for a range of key variables such as the Strouhal and Froude numbers, unsteady parameter, and the depth of foil submergence. New results obtained in this work reveal complex interactions between the flap-motion generated waves and vortices, in particular, how the deforming free surface above the vehicle and radiating surface waves could affect the generation and evolution of shed vortices and the thrust-generating capacity of flapping foils. Necessary conditions for high propulsive efficiency are found to be (i) Strouhal number between 0.25 and 0.35 and (ii) oscillation at supercritical frequency, i.e., τ > 0.25. At the critical frequency τ = 0.25 the efficiency is found to be low particularly when the body is very to the free surface. Upstream wave propagation at sub-critical frequency τ < 0.25 results in the loss of propulsive efficiency. Mechanisms affecting the efficiency are amplified by the foil proximity to the surface. In the case of flapping hinged double foil, in-phase oscillation of the foils results in high thrust while out-of phase flapping produces nearly null mean thrust. Flapping of twin foil in the “clapping mode” results in a pulsating wake jet yielding a large thrust but requiring large torque and hence at low efficiency. Efficiencies upto 80% are found in the simulations with single foil.
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Rana, R. K., N. Johnson, P. Dongare, and S. Barve. "Is there a case for emulating a fish or other sea borne creatures for propulsion of underwater vehicles?" In 14th International Naval Engineering Conference and Exhibition. IMarEST, 2018. http://dx.doi.org/10.24868/issn.2515-818x.2018.018.

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Fish and other sea borne creatures have invoked interest in the minds of many professionals to study how they propel themselves in water and whether similar principles can be applied to the design of underwater vehicles. Adopting these principles for propulsion had been a challenge some decades ago, but with the current technological progress in robotics, design analysis, advanced computing, precision manufacturing, 3D printing, sensors, actuation, image processing etc have rekindled an interest in this field, especially in the Indian context. Moreover, with the thrust on development of unmanned autonomous systems, especially for the naval warfare, there is a case for looking at an efficient way to propel such vehicles that can stay underwater for a longer duration, move and navigate faster than those traditionally shaped and propelled by screw propellers or pump jets. This paper looks at some of the basics of fish locomotion; technology trends; examples of the current developments; benefits of emerging technologies, investigate performance of some basic shapes of caudal fin of fish with the help of modern analytical tools such as Computational Fluid Dynamics and the way ahead.
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Shipeng, Li, Yunlong Tang, Xiao Y. Zhang, Zhu Liu, and Ningfei Wang. "Numerical Investigation on the Flow Structure of Gaseous Jet Horizontally Injected into Water for Underwater Propulsion." In 55th AIAA Aerospace Sciences Meeting. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2017. http://dx.doi.org/10.2514/6.2017-1701.

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Bandyopadhyay, Promode R. "Flying Fish Sculls to Taxi and Perturbs Wing Lift With Travelling Waves to Land." In ASME 2016 Fluids Engineering Division Summer Meeting collocated with the ASME 2016 Heat Transfer Summer Conference and the ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/fedsm2016-7507.

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The top 200 meters of oceans abound in life forms since photosynthesis is possible in that layer. Competition and predator-prey (swordfish-flying fish, 102–104 to 1 mass ratio) interactions are intense here. Chased by predators, a flying fish (FF) — a pleuston — frantically escapes from the water and becomes airborne. Here we report the visual observations of oceanic surface and body distortions of FF to surmise the mechanisms of propulsion during taxiing and landing. FF leaps, not when it is chased, but when the additional energy required for further increase in speed underwater exceeds that required to leap.1 The higher metabolic cost of transport of regular flapping flight in air than in water is circumvented by gliding. We examine the BBCTV video2 by Richard Attenborough, the noted naturalist. An FF may camber its wings like parafoils and may also twist the outer half of the wings during taxiing and climbing. To produce thrust during taxiing, the FF sculls with the lower lobe of the tail fin to produce a reverse Karman vortex jet; there is rapid flicking of the lower lobe of the tail fin tangentially over the surface. The body acts as a chaotic damped and driven pendulum to produce the high-velocity wide flick. To damp after takeoff, it becomes a single asymmetric pendulum. Unpowered (foil) gliding follows. For descent, the wings are shaped, untwisted parafoils and, just prior to touchdown, travelling waves are superimposed, producing, in contrast to taxiing, an impressively smooth small-angle-of-attack tail touchdown on water without any nose-down. The spiked crowns of Richtmyer-Meshkov interface instability are visible on the ocean surface during leaping but not during landing. Trailing hydraulic jumps are observable during landing but not during leaping. The leap is a high-acceleration and Weber number dominated (inertia/capillary forces) phenomenon, but the landing involves little impact force and is dominated by Froude number forces (inertia/gravity forces). The evidence suggests that, prior to leaping and while still underwater, the FF reads the surface wind direction to align the flight path.
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LIN, T., J. GILBERT, and G. D. ROY. "Performances of Underwater Vehicles Using Sea-Water Magnetohydrodynamic Propulsion." In 26th Joint Propulsion Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1990. http://dx.doi.org/10.2514/6.1990-2475.

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Balepin, Vladimir, Christopher Osello, and Christopher Snyder. "NOX Emission Reduction in Commercial Jets through Water Injection." In 38th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2002. http://dx.doi.org/10.2514/6.2002-3623.

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