Experimental and numerical investigation of water impact on air-launched AUVs

Yan, Gen; Pan, Guang; Shi, Yue; Chao, Li-Ming; Zhang, Dong

doi:10.1016/j.oceaneng.2018.08.044

Cited by 58 publications

(11 citation statements)

References 26 publications

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“…It is also equipped with precision-navigation and terrain-following features, as well as a sophisticated collision avoidance system. Other relevant implementations are air-deployable and launchable AUVs [54]. Although most of these implementations focused on aerial deployment of traditional REMUS-type vehicles [55], a NERC-funded project investigated the use of highly portable small-scale AUVs, weighting just 2.5 kg, with a range of 350 km at speeds of 0.5 ms-1 [56].…”

Section: The Enduruns Overall Approachmentioning

confidence: 99%

ENDURUNS: An Integrated and Flexible Approach for Seabed Survey Through Autonomous Mobile Vehicles

Marini

Gjeci²,

Govindaraj

et al. 2020

JMSE

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The oceans cover more than two-thirds of the planet, representing the vastest part of natural resources. Nevertheless, only a fraction of the ocean depths has been explored. Within this context, this article presents the H2020 ENDURUNS project that describes a novel scientific and technological approach for prolonged underwater autonomous operations of seabed survey activities, either in the deep ocean or in coastal areas. The proposed approach combines a hybrid Autonomous Underwater Vehicle capable of moving using either thrusters or as a sea glider, combined with an Unmanned Surface Vehicle equipped with satellite communication facilities for interaction with a land station. Both vehicles are equipped with energy packs that combine hydrogen fuel cells and Li-ion batteries to provide extended duration of the survey operations. The Unmanned Surface Vehicle employs photovoltaic panels to increase the autonomy of the vehicle. Since these missions generate a large amount of data, both vehicles are equipped with onboard Central Processing units capable of executing data analysis and compression algorithms for the semantic classification and transmission of the acquired data.

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Section: The Enduruns Overall Approachmentioning

confidence: 99%

ENDURUNS: An Integrated and Flexible Approach for Seabed Survey Through Autonomous Mobile Vehicles

Marini

Gjeci²,

Govindaraj

et al. 2020

JMSE

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“…Because flying drones and underwater vehicles have been strongly researched and because drones experience a higher potential for losing integrity when transitioning between mediums, the components of a flying, diving, and swimming drone in need of more analysis are the dive into water and the exit back into air. Due to a higher risk of drone malfunction after impacting water during fast transitions [12], this study is interested in the dive component of flying, diving and swimming drones. The Gannet is a diving bird found in nature able to successfully impact water continuously at high speeds averaging 24 m s −1 [13].…”

Section: Introductionmentioning

confidence: 99%

Enhanced design considerations on the buckling and dynamics of Gannet-inspired systems during water entry

Zimmerman

Abdelkefi

2020

Bioinspir. Biomim.

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To provide a more complete analysis of Gannet birds and Gannet-inspired drones during diving, this work considers an improved beam model to describe the static and dynamic characteristics of Gannet and Gannet-like drones at impact. The beam model consists of two different geometric and material property beams under continuity conditions to better understand the geometrical and material parameters’ influence on the structural statics and dynamics of these kinds of systems. Using Hamilton’s principle, the equations of motion, continuity, and boundary conditions considering Euler–Bernoulli and Timoshenko theories are derived. Then, applying the continuity and boundary conditions, the static and dynamic analyses are conducted to examine the impact buckling speeds, the buckled shapes, the natural frequencies at different impact velocities for bioinspired drone design, and the post-buckled mode shapes. The buckled configurations suggest that the body of the Gannet most likely has a different bending and torsional stiffness than the neck. The results indicate that the amount of softening in the joints contributes significantly to not only the speed at which the bird will buckle, but also the buckling profile of the bird. To obtain a physical buckling profile of the Gannet, a stiffer boundary condition at the end of the bird body model is needed due to the increased bending stiffness properties of the body compared to the neck as well as the position of the wings and feet surpassing the end of the body. The results also demonstrate that to build a bioinspired diving drone that falls within a smaller air-vehicle range, the amount of error between theories in predicting the static and dynamic buckling behavior of the system becomes significantly more evident. The dynamic characteristics and mode shapes of the Gannet-like systems are provided for further drone design insight on the impact speeds the drone can achieve without responding to an external excitation frequency from a propeller or actuator.

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“…Dedicated single-arm crane systems are very safe, as shown in Figure 2. They greatly simplify operation processes and save costs [11]; however, time-consuming deployment and its inefficiency to quickly launch multiple AUVs to target sea areas are its weaknesses. Sliding-type crane systems are mainly used to continuously lay equipment or different types of remotely operated vehicle (ROV) cables.…”

Section: Introductionmentioning

confidence: 99%

“…Wang et al [17] established an oblique water entry impact model, coupled with dynamic ballistic models, which was based on the theory of potential flow and the precise shape of the coupling surface between the fluid and the solid. In particular, airborne launch methods that use planes or helicopters to quickly launch AUVs into target sea areas have received more attention by scientists and strategists recently [11][12][13][14][15][16][17][18][19][20][21]. Scholars have conducted a lot of research to investigate water entry impact forces, trajectory deflection, and damage to an airborne-launched AUV, especially when the maximum impact loads occur in the initial entry stages [11].…”

Section: Introductionmentioning

confidence: 99%

Computational Fluid Dynamics Study of Water Entry Impact Forces of an Airborne-Launched, Axisymmetric, Disk-Type Autonomous Underwater Hovering Vehicle

Chen

2019

Symmetry

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An autonomous underwater hovering vehicle (AUH) is a novel, dish-shaped, axisymmetric, multi-functional, ultra-mobile submersible in the autonomous underwater vehicle (AUV) family. Numerical studies of nonlinear, asymmetric water entry impact forces on symmetrical, airborne-launched AUVs from conventional single-arm cranes on a research vessel, or helicopters or planes, is significant for the fast and safe launching of low-speed AUVs into the target sea area in the overall design. Moreover, a single-arm crane is one of the important ways to launch AUVs with high expertise and security. However, AUVs are still subject to a huge load upon impact during water entry, causing damage to the body, malfunction of electronic components, and other serious accidents. This paper analyses the water entry impact forces of an airborne-launched AUH as a feasibility study for flight- or helicopter-launched AUHs in the future. The computational fluid dynamics (CFD) analysis software STAR-CCM+ solver was adopted to simulate AUH motions with different water entry speeds and immersion angles using overlapping grid technology and user-defined functions (UDFs). In the computational domain for a steady, incompressible, two-dimensional flow of water with identified boundary conditions, two components (two-phase flow) were modeled in the flow field: Liquid water and free surface air. The variations of stress and velocity versus time of the AUH and fluid structure deformation in the whole water entry process were obtained, which provides a reference for future structural designs of an AUH and appropriate working conditions for an airborne-launched AUH. This research will be conducive to smoothly carrying out the complex tasks of AUHs on the seabed.

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Experimental and numerical investigation of water impact on air-launched AUVs

Cited by 58 publications

References 26 publications

ENDURUNS: An Integrated and Flexible Approach for Seabed Survey Through Autonomous Mobile Vehicles

ENDURUNS: An Integrated and Flexible Approach for Seabed Survey Through Autonomous Mobile Vehicles

Enhanced design considerations on the buckling and dynamics of Gannet-inspired systems during water entry

Computational Fluid Dynamics Study of Water Entry Impact Forces of an Airborne-Launched, Axisymmetric, Disk-Type Autonomous Underwater Hovering Vehicle

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