Article
Engineering, Ocean
Arun Kamath, Weizhi Wang, Csaba Pakozdi, Hans Bihs
Summary: Increasing offshore wind turbine deployment is crucial for boosting green renewable energy production. Efficient identification of extreme events and evaluation of hydrodynamic loads are vital for cost reduction. Numerical modeling helps to pre-screen sea states, prioritizing model tests and minimizing design times and costs.
JOURNAL OF OFFSHORE MECHANICS AND ARCTIC ENGINEERING-TRANSACTIONS OF THE ASME
(2023)
Article
Engineering, Marine
Li Xiao, Kezhao Fang, Minghan Huang, Dongxu Wang, Zhongbo Liu
Summary: This paper presents flume experiments and numerical simulations of focused wave group propagation over an idealized fringing reef profile and its impact on the vertical wall mounted on reef flat. The results show that the low frequency wave motion contributes significantly to the total force exerted on the wall. The geometry characters of fringing reef and focusing position also have an effect on the maximum horizontal force on the vertical wall.
Article
Engineering, Marine
Fen Liu, Tian Lan, Zhan Wei, Xiujun Sun, Shuai Zhang, Hongqiang Sang, Fang Huang
Summary: This study proposes an improved adaptive model predictive control method based on model predictive control and adaptive algorithm to address the nonlinear effects caused by the interaction between the propeller and the rudder in the wave glider's dual-body structure. By considering constraints, time-varying velocities, and external disturbances, adaptive adjustments of the rudder and propeller are implemented to ensure accuracy and speed in control.
Article
Engineering, Marine
Kai Yin, Sudong Xu, Wenrui Huang, Ming Lin
Summary: Understanding the dynamics of flexible vegetation and its interaction with waves is crucial for studying wave attenuation. Existing studies have limitations, focusing on submerged vegetation and linear wave assumptions. This study develops a new mechanical model and conducts wave flume experiments to investigate emergent flexible vegetation dynamics. The results reveal the influencing factors and validate the reliability and usefulness of the model. This study optimizes the simulation theory and method of wave-induced flexible vegetation dynamics and provides new insights into the interaction between coastal flexible vegetation and waves.
Article
Engineering, Marine
V. Sanil Kumar, A. Anusree
Summary: This study examines the characteristics of high waves generated by tropical cyclones in coastal waters of India. The results show that the influence of cyclones on wave heights is short-lived, lasting only for three days, with an average decrease in wave height of 0.17m per hour.
Article
Engineering, Marine
Junjie Wang, Renliang Chen, Zhiming Yu, Jiaxin Lu
Summary: Ground and water interferences significantly affect the safety of takeoff and landing for Quad Tilt-Rotor (QTR) aircraft. An unsteady numerical simulation method suitable for amphibious QTR aircraft is established and verified through ground tests. The study explores the distinct aerodynamic characteristics of the QTR aircraft in water and ground effects (IWE and IGE) and compares them to those out of ground effect (OGE). Results indicate that the wing, ground or water surface strongly affects the QTR's aerodynamic performance by influencing the downwash flow form the rotors. The lift and torque coefficients exhibit irregular fluctuations during IGE compared with OGE. However the distribution of lift and torque coefficients become more periodic and regular during IWE due to the flexible water surface.
Article
Engineering, Marine
Kenneth Weems, Vadim Belenky
Summary: SimpleCode is a fast time-domain simulation tool for ship motion in waves, implementing a body-nonlinear formulation and providing a general reduced-order numerical model of ship motions. It has been used for statistical validation and identification of extreme response events in seakeeping analysis.
Article
Engineering, Marine
Ilan Robin, Dominique Mouaze, Anne-Claire Bennis, Guillaume Carpentier
Summary: This study evaluates the applicability of the overset method in modeling new-generation turbines, demonstrating its potential for solving problems that cannot be addressed by conventional CFD methods. The overset method allows for controlled blade motion without loss of information.
Article
Engineering, Marine
Xianyi Zhai, Honglei Wei, Hongda Wu, Qing Zhao, Meng Huang
Summary: This article introduces an underwater multi-target tracking algorithm for aquaculture monitoring using deep learning techniques. By improving image processing and object detection algorithms, stable and efficient fish tracking is achieved.
Article
Engineering, Marine
Ki Hong Ten, Hooi-Siang Kang, Chee-Loon Siow, Pei Sean Goh, Kee-Quen Lee, Sharin Hazlin Huspi, C. Guedes Soares
Summary: This paper provides an overview of the latest developments and applications of data-driven studies using Automatic Identification System (AIS) in order to control carbon emissions from maritime transportation. The paper emphasizes the importance of AIS data in assessing ship emissions and their environmental impact. AIS data's wide range of information types, coverage, and frequency make it superior to other maritime information services, allowing for in-depth correlation studies. The paper suggests that AIS data can be further utilized in various analytical applications such as Estimated Time of Arrival predictions, emission projections, and decision support systems for ships. Additionally, AIS data's flexibility for integration with other data sources, such as weather routing and smart inland shipping, can contribute to a seamless system. The ultimate goal of these studies is to contribute to a "green" and "smart" maritime sector through efficient processes and minimal energy waste.
Article
Engineering, Marine
Hancheng Huang, Qingwei Liang, Shanshan Hu, Cheng Yang
Summary: A novel meta-heuristic assisted method is proposed for the deployment of multi-blended-wing-body underwater gliders (BWBUGs) in this study. The deployment optimization model is established by combining the detection coverage ratio and all-terminal reliability, and a Levy flight with visual expansion (LVE) is used to enhance the search capability. An LVE-enhanced whale optimizer (LVEWO) is proposed for improving the quality of the initial population and the search strategy. Simulation experiments demonstrate the effectiveness of the proposed deployment model and the competency of LVEWO. The comprehensive performance of LVEWO is better than other algorithms.
Article
Engineering, Marine
Chengfeng Jia, Jie Ma, Xin Yang, Xiaolei Lv
Summary: Ship trajectory prediction is crucial for ensuring safety in dense waterway traffic. This paper proposes a risk-aware trajectory prediction framework, RAGAN, based on Generative Adversarial Network, to accurately predict ship trajectories and collision avoidance strategies in multi-ship encounters. Through adversarial training and an interacting gate function, RAGAN effectively captures risks and influences in encounter situations, demonstrating the ability to learn beyond existing regulations.
Article
Engineering, Marine
Yunbiao Jiang, Fuyong Wang, Haomiao Yu, Chen Guo, Zhongxin Liu
Summary: This paper investigates the containment control problem of multiple unmanned surface vehicles (USVs) with directed communication topology. It proposes a fully-distributed adaptive containment controller that combines an event-triggered quantized (ETQ) control strategy and an improved prescribed-time control technique. The controller utilizes backstepping method, finite-time differentiators, neural networks, and parametric adaptive techniques. It is shown that the controller effectively reduces the calculation and channel burden while maintaining control performance.
Article
Engineering, Ocean
Yu Wang, Hamn-Ching Chen
Summary: In this study, an extensive verification and validation analysis was conducted to evaluate the accuracy and credibility of computational fluid dynamic (CFD) simulations of the hydrodynamic responses of a semi-submersible floating offshore wind turbine (FOWT) platform under bichromatic waves and random waves. The results show that the use of CFD code provides more consistent results with experimental values.
JOURNAL OF OFFSHORE MECHANICS AND ARCTIC ENGINEERING-TRANSACTIONS OF THE ASME
(2023)
Article
Engineering, Marine
Zhang Shi, Aiqin Li
Summary: This study proposes a target underwater motion situation model (TUMS) that can predict the underwater motion trajectory and landing positions of targets, taking into account random factors such as waves and currents. The numerical simulation results are in good agreement with experimental results, indicating that the model has significant implications for the motion mode of underwater structures.
Article
Engineering, Marine
Biao Nie, Shanhua Xu, Huapeng Chen, Min Xia, Wenjie Guo
Summary: This study investigates the effect of corrosion on the bearing capacity of cold-formed steel channel section columns. Through experiments and finite element modeling, it is found that corrosion leads to increased geometric imperfections, early occurrence of distortional buckling deformation, and the failure locations are mainly related to flange corrosion.
Article
Engineering, Marine
Yeqi Cao, Qiang Xu, Tianyu Liu, Haiyang Yu, Bo Huang, Liejin Guo
Summary: This study obtained data on long hydrodynamic slugs at high liquid velocity and low gas velocity through experimental observations, and found that slug flow can occur at a lower superficial gas velocity in long pipelines.
Article
Engineering, Marine
Bin Teng, Ziqi Li, Longfei Cong, Jinlu Sheng
Summary: This work investigates the generalized hydrodynamic coefficients of connected twin circular cylinders. The study applies a matched boundary element method with eigen-function expansion to analyze the hydrodynamic coefficients of floating and submerged tunnels with twin horizontal cylinders in finite water depth. The study finds that the gap resonance problem can be ignored for submerged floating tunnels with a certain submergence depth, and the axial wave number plays a crucial role in the added mass. Analytic solutions are then derived for the high frequency approximations of the generalized added masses of twin connected cylinders. The hydrodynamic interference between the two cylinders can be neglected when certain conditions are met, allowing for the derivation of generalized added mass coefficients from those of single isolated cylinders.
Article
Engineering, Marine
Xing Chen, Binrong Wen, Xinliang Tian, Shuyue Sun, Peng Wang, Xin Li
Summary: This paper proposes a reinforcement learning based control strategy for autonomous decision-making of robotic fishtails in complex flows. The experimental results confirm the superiority of the control strategy in terms of accuracy, stability, and response speed.
Article
Engineering, Marine
Cuong Mai Bui, Thinh Xuan Ho
Summary: This study numerically investigates the flow characteristics of kaolinite mixed with water passing a cylinder near a moving wall. The results show that the flow regime is influenced by the gap ratio, Reynolds number, and Bingham number. At small gaps, the drag and lift coefficients increase with decreasing gap size.
