CFD-based hydrodynamic performance investigation of autonomous underwater vehicles: A survey

Ocean Engineering, Journal Year: 2024, Volume and Issue: 305, P. 117911 - 117911

Published: April 24, 2024

Language: Английский

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Influence of Vehicle Wake on the Control of Towed Systems

Applied Sciences, Journal Year: 2024, Volume and Issue: 14(11), P. 4944 - 4944

Published: June 6, 2024

The hydrodynamic wake generated by the underwater vehicle’s motion has a considerable impact on movement of towed system underwater. This paper utilizes lumped mass method to model cable in order improve accuracy predicting its position and attitude wake, determine suitable cable-towed position. Velocity is transferred from flow field dynamic an innovative way imitate cable. Several iterations are conducted enhance reactivity system. Numerical simulations used both straight turning movements. numerical calculation provides characteristics vorticity formed energy exchange between cable, as well gradually dissipating momentum at trailing edge enclosure. results indicate that best location for where does not cause any adhesion. On other hand, disadvantageous scenario systems occurs when cable’s causes substantial innovatively establishes mechanical exchange, describes fluid dynamics, divides four regions motion. In manipulation state, transient vibration response structure coupling can accurately separation region point vehicle based compatibility (non-adhesive) incompatibility (adhesive). boundary defined distinguish free tow wall-attached point. A transition zone possibility change pattern tow. be divided into region, zone, adjacent wall this interaction assessment method.

Language: Английский

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Output fault-tolerant control of underwater vehicle based on adaptive sliding mode control under multiple constraints

Proceedings of the Institution of Mechanical Engineers Part M Journal of Engineering for the Maritime Environment, Journal Year: 2024, Volume and Issue: unknown

Published: June 19, 2024

In order to improve the stability of underwater vehicle, output fault-tolerant control method vehicle based on adaptive sliding mode is designed basis setting multiple constraints. After dynamic analysis and its thruster, dimension constraint, input amplitude state constraint were set. Based these three constraints, recursive cerebellar neural network used identify time-varying nonlinear unknown faults in online, a deep convolution detect known vehicle. The error correction code then combined with support vector machine classify detected faults. Finally, an realized control. experiment shows that after application this method, because can estimate size fault information time, controller readjust according result identification offset effect robot, so robot continue maintain original stable operation state. Even if thruster has faults, adjust time reconstruct recover total output, actual thrust very close expected value, achieve output.

Language: Английский

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Numerical analysis of dynamic behaviors of underwater towed system with hydrofoil manipulations

Ocean Engineering, Journal Year: 2024, Volume and Issue: 310, P. 118791 - 118791

Published: July 27, 2024

Language: Английский

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Numerical Analysis of Dynamic Behaviors of Underwater Towed System with Hydrofoil Manipulations

Published: Jan. 1, 2024

This paper addresses the challenge of dynamic characteristics an underwater towed system under manipulations synchronous hydrofoils. A hydrodynamic model coupled with hydrofoil control algorithms is presented, forces on hydrofoils and Underwater Towed Vehicle (UTV) are simulated using Computational Fluid Dynamics (CFD) method, fluid Towing Cable (TC) described a flexible cable model. The behaviors depth-undulating, depth-tracking, depth-keeping controls analyzed experimentally validated results show that towing speed has significant effect efficiency hydrofoils, higher speed, greater responses system, system's asymmetric within one oscillation cycle. increase or decrease more significantly in depth-tracking operations than freely due to hydrofoils' manipulations. can achieve satisfactory effects submerged depth for vehicle at appropriate whereas it fails lower noticeable response oscillations occur simultaneously.

Language: Английский

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Dynamics Modeling and Motion Evaluation of a Near-Ground Tethered Balloon Cable System under Severe Wind Environments

Actuators, Journal Year: 2024, Volume and Issue: 13(10), P. 402 - 402

Published: Oct. 5, 2024

Weather survival poses a significant challenge for the utilization of tethered balloons. The dynamic modeling balloon systems presents challenges due to flexible nature cables and intricate gust forces. present study introduces new approach near-ground systems, which enables analysis their responses performance evaluation under complex boundary conditions. First, finite cylindrical rigid bodies that are joined together by bushing forces describe dynamics cable. properties severe bending translation can be illustrated model. Second, three-dimensional model based on multibody theory is created deal with interaction system cables. challenging operating conditions investigated, focusing number cable segments place direction wind impacts. This allows precise assessment optimization system’s overall improve weather resistance. results show compared computational fluid (CFDs) methods, dynamics-based improved solution time 80%, pitch angle deviation only 0.0016°. Moreover, effectively reduced force enabled accurate reflection motion characteristics.

Language: Английский

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Study on the impact of asymmetric design on the hydrodynamic characterization of the disk-shaped autonomous underwater helicopter surging near the seabed

Physics of Fluids, Journal Year: 2024, Volume and Issue: 36(12)

Published: Dec. 1, 2024

Hydrodynamic characteristics of autonomous underwater vehicles (AUVs) are significantly changed when they close to the seabed boundary. In this study, hydrodynamic performance a newly developed disk-shaped AUV—the helicopter (AUH) near bottom boundary is investigated. The hull-shape modification into an asymmetric hull geometry was proposed improve near-bottom and guide future work on AUH profile optimization. It indicated that multiple zero-velocity regions formed beneath vessel it surges This induced intricate interactions layers between seabed. Moreover, abrupt evolution could induce strong shear vortices boundary, potentially causing phenomena like flow separation reattachment. designed reduce bulge increase area horizontal region, which considerably reduced drag meanwhile increased stability. Furthermore, two mechanisms depending namely, blocking effect leads both higher lift acceleration reduces lift, were suggested explain alteration

Language: Английский

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