Article
Engineering, Ocean
Chuntong Li, Deyu Wang, Jiaqi Liu, Zhonghua Cai
Summary: This study investigated the dynamic responses of lashing force, twist lock force, and container stack displacement under close to real conditions, revealing that external lashing is preferable to internal lashing when encountering high stack and heavy stowage. Additionally, reducing the gap can minimize stack displacement and lashing force, but is not an effective solution to reduce twist lock force. Mutual coupling effects exist between lashing methods, lashing force, twist lock force, and twist lock gap.
APPLIED OCEAN RESEARCH
(2021)
Article
Engineering, Marine
Chuntong Li, Zhonghua Cai, Deyu Wang
Summary: This study investigates the dynamic mechanical behavior of a seven-tier 20-ft ISO freight container single stack and lashing devices under combined rolling and pitching excitation. Through experiments and numerical simulations, it is found that a reasonable lashing configuration can decrease the dynamic response of the system, and a proper horizontal gap is crucial in preventing shear forces from exceeding allowable values.
SHIPS AND OFFSHORE STRUCTURES
(2022)
Article
Engineering, Marine
Chuntong Li, Deyu Wang, Zhonghua Cai
Summary: The study proposed an experimental research method to measure the dynamic response of safer container shipping under heavy sea states. By conducting experiments on scaled models and eleven container scaled models, the results of experiments, numerical simulations, and calculations of the VERISTAR procedure were compared.
Article
Engineering, Marine
Chuntong Li, Deyu Wang, Zhonghua Cai
Summary: Progress has been made in design innovation for ultra-large container ships, focusing on the mechanical behavior of lashing bridges. Finite element analysis and experiments were used to study the static and dynamic characteristics, revealing the importance of the coupling effect between the lashing bridge and hull structure.
SHIPS AND OFFSHORE STRUCTURES
(2021)
Article
Physics, Fluids & Plasmas
Yue Liu, Dahai He
Summary: Based on the geometrization of dynamics and self-consistent phonon theory, an analytical approach is developed to derive the Lyapunov time for general nonlinear lattices. The universal scaling behavior of the Lyapunov time with the nonintegrability strength is observed for the quasi-integrable regime, with the scaling exponent being the same as the thermalization time. This proportional relationship indicates how the thermalization process is related to the intrinsic chaotic property.
Article
Environmental Sciences
Wenjing Lu, Yuchen Du, Rongqiang Fu, Ming Tan, Guizhong Zhou, Veeriah Jegatheesan, Yang Zhang
Summary: In this study, electrodialysis was used to treat a colloidal saline solution, and the influence of different factors on the geometry and dynamics of colloids was investigated. The study confirmed that colloid aggregation was the cause of clogging during electrodialysis.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Mechanics
Amin Mivehchi, Qiang Zhong, Melike Kurt, Daniel B. Quinn, Keith W. Moored
Summary: This study presents scaling laws for the thrust production and power consumption of a purely pitching hydrofoil in ground effect, capturing a wide range of biologically relevant parameters based on physical insights. The scaling laws, validated by both inviscid simulations and viscous experiments, can accelerate the design of bio-inspired hydrofoils oscillating near the ground or arranged side by side with two out-of-phase foils.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Engineering, Mechanical
Yuanhang Zhu, Howon Lee, Sushrut Kumar, Karthik Menon, Rajat Mittal, Kenneth Breuer
Summary: This study experimentally investigates the dynamics and strength of vortices shed from a NACA 0012 wing during sinusoidal pitching in quiescent water. The vortex trajectory and circulation are analyzed over a range of pitching frequencies, amplitudes, and pivot locations. By utilizing a physics-based force and moment partitioning method (FMPM), the vortex-induced aerodynamic moment is estimated from measured velocity fields. The results show that the vortex circulation, formation time, and vorticity-induced moment follow scaling laws based on the feeding shear-layer velocity. The study also demonstrates the capability of FMPM in dissecting experimental flow field data and providing insights into the underlying flow physics.
EXPERIMENTS IN FLUIDS
(2023)
Article
Engineering, Marine
Jiaqi Liu, Chuntong Li, Deyu Wang, Zhonghua Cai
Summary: This study investigates the dynamic effects caused by hull movement on container stack and securing system through experiments and numerical simulations. It is found that proper cargo configuration and decreasing twist lock gap can enhance the safety of the container stack.
SHIPS AND OFFSHORE STRUCTURES
(2022)
Article
Mechanics
Yuanhang Zhu, Varghese Mathai, Kenneth Breuer
Summary: The study experimentally investigates the nonlinear fluid damping of a rigid but elastically mounted pitching wing in the absence of a free-stream flow, proposing a universal fluid damping scaling to incorporate different parameters. The fluid damping coefficient is measured from damped oscillations over a wide range of conditions, and flow fields obtained using particle image velocimetry are analysed to explain the nonlinear behaviors of the fluid damping.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Engineering, Marine
Jeremie Labasse, Uwe Ehrenstein, Guillaume Fasse, Frederic Hauville
Summary: The Chimera method, in combination with the OpenFOAM toolbox, is used to numerically compute the forces generated by large amplitude heaving and pitching foil. The study explores the possibility of fitting thrust prediction laws, based on classical potential flow theories, with the numerically computed forces at a Reynolds number of 5×104. The results show that theoretical scaling can be applied to numerical time-averaged thrust data even in the case of large amplitude motions, and the thrust-prediction law is still applicable to pitching-rotating motions.
Article
Engineering, Aerospace
Neil Wu, Charles A. Mader, Joaquim R. R. A. Martins
Summary: This work proposes a sensitivity-based geometric parametrization approach to improve the convergence speed and effectiveness of aerodynamic shape optimization.
Article
Multidisciplinary Sciences
Million Gebreyes, Kindu Mekonnen, Peter Thorne, Melkamu Derseh, Aberra Adie, Annet Mulema, Seid Ahmed Kemal, Lulseged Tamene, Tilahun Amede, Amare Haileslassie, Aster Gebrekirstos, Walter Tamuka Mupangwa, Mohammed Ebrahim, Temesgen Alene, Addisu Asfaw, Workneh Dubale, Simret Yasabu
Summary: Scaling in agricultural research globally requires a balance between technical requirements and social dynamics, with a focus on relationships, trust, and continuous learning. Flexibility, stepwise approaches, and reflection are essential for successful scaling strategies to overcome critical constraints in agricultural innovation scaling.
Article
Mathematics
Toni Annala, Ryomei Iwasa
Summary: This study proves that on derived schemes, for a Zariski sheaf of ring spectra E equipped with finite quasi-smooth transfers and satisfying projective bundle formula, E*(Vect(n,S)) can be freely generated by Chern classes c(1), . . . ,c(n) over E*(S).
ADVANCES IN MATHEMATICS
(2022)
Article
Computer Science, Information Systems
Nisarg S. Joshi, Raghav Raghuwanshi, Yash M. Agarwal, B. Annappa, D. N. Sachin
Summary: Containerization has become a widely used virtualization mechanism for deploying applications and services in the cloud alongside Virtual Machines (VMs). This work introduces a novel mechanism for auto-scaling containers in cloud environments by utilizing predictive analysis with the ARIMA model and control theory with the PID controller. Experimental results demonstrate the superior performance of the proposed ARIMA-PID algorithm in terms of CPU utilization and average response times.
MULTIMEDIA TOOLS AND APPLICATIONS
(2023)
Article
Engineering, Marine
Alba Ricondo, Laura Cagigal, Beatriz Perez-Diaz, Fernando J. Mendez
Summary: This research presents a site-specific metamodel based on the SWASH numerical model simulations, which can predict coastal hydrodynamic variables in a fast and efficient manner. The metamodel uses downscaled and dimensionality reduced synthetic database to accurately reproduce wave setup, wave heights associated with different frequency bands, and wave runup. This method has great potential in coastal risk assessments, early warning systems, and climate change projections.
Article
Engineering, Marine
Xiao Yu, Wangjun Ren, Bukui Zhou, Li Chen, Xiangyun Xu, Genmao Ren
Summary: This study investigated and compared the compression responses and energy absorption capacities of coral sand and silica sand at a strain rate of approximately 1000 s-1. The results showed that coral sand had significantly higher energy absorption capacity than silica sand due to its higher compressibility. The study findings suggest that using poorly graded coral sand can improve its energy absorption capacity.
Article
Engineering, Marine
Jingxi Zhang, Junmin Mou, Linying Chen, Pengfei Chen, Mengxia Li
Summary: This paper proposes a cooperative control scheme for ship formation tracking based on Model Predictive Control. A predictive observer is designed to estimate the current motion states of the leader ship using delayed motion information. Comparative simulations demonstrate the effectiveness and robustness of the proposed controller.
Article
Engineering, Marine
Yu Yao, Danni Zhong, Qijia Shi, Ji Wu, Jiangxia Li
Summary: This study proposes a 2DH numerical model based on Boussinesq equations to investigate the impact of dredging reef-flat sand on wave characteristics and wave-driven current. The model is verified through wave flume experiments and wave basin experiments, and the influences of incident wave conditions and pit morphological features on wave characteristics are examined.
Article
Engineering, Marine
Jayanta Shounda, Krishnendu Barman, Koustuv Debnath
Summary: This study investigates the double-average turbulence characteristics of combined wave-current flow over a rough bed with different spacing arrangements. The results show that a spacing ratio of p/r=4 offers the highest resistance to the flow, and the double-average Reynolds stress decreases throughout the flow depth. The advection of momentum-flux of normal stress shows an increase at the outer layer and a decrease near the bed region after wave imposition. Maximum turbulence kinetic energy production and diffusion occur at different layers. The turbulence structure is strongly anisotropic at the bottom region and near the outer layer, with a decrease in anisotropy observed with an increase in roughness spacing.
Article
Engineering, Marine
Meng Zhang, Lianghui Sun, Yaoguo Xie
Summary: The research proposes a method for online identification of wave bending and torsional moment in hull structures. For structures without large openings, the method optimizes sensor positions and establishes a mathematical model to improve accuracy. For structures with large openings, a joint dual-section monitoring method is proposed to simultaneously identify bending and torsional moments in multiple key cross sections.
Article
Engineering, Marine
Longming Chen, Shutao Li, Yeqing Chen, Dong Guo, Wanli Wei, Qiushi Yan
Summary: This study investigated the dynamic response characteristics and damage modes of pile wharves subjected to underwater explosions. The results showed that the main damaged components of the pile wharf were the piles, and inclined piles had a higher probability of moderate or more significant damage compared to vertical piles. The study also suggested that replacing inclined piles with alternative optimized structures benefits the blast resistance of pile wharves.
Article
Engineering, Marine
I. -C Kim, G. Ducrozet, V. Leroy, F. Bonnefoy, Y. Perignon, S. Bourguignon
Summary: Previous research focused on the accuracy and efficiency of short-term wave fields in specific prediction zones, while we developed algorithms for continuous wave prediction based on the practical prediction zone and discussed important time factors and strategies to reduce computational costs.
Article
Engineering, Marine
Hang Xie, Xianglin Dai, Fang Liu, Xinyu Liu
Summary: This study investigates the load characteristics of a three-dimensional stern model with pitch angle through a drop test, and reveals complex characteristics of pressure distribution near the stern shaft. The study also shows that the vibration characteristics of the load are influenced by the drop height and pitch angle, with the drop height having a greater effect on the high-frequency components.
Article
Engineering, Marine
Hangyuan Zhang, Wanli Yang, Dewen Liu, Xiaokun Geng, Wangyu Dai, Yuzhi Zhang
Summary: The deep-water bridge is more vulnerable to earthquake damage than the bridge standing in air. The larger blocking ratio has a significant impact on the added mass coefficient, which requires further comprehensive study. The generation mechanism of block effect is analyzed using numerical simulation software ANSYS Fluent. The results show that the recirculation zone with focus reduces the pressure on the back surface of the cylinder, resulting in the peak value of in-line force not occurring synchronously with the peak value of acceleration. The change in position and intensity of the recirculation zone with focus, as well as the change in water flow around the cylinder surface, are identified as the generation mechanism of the block effect, which has a 10% influence on the hydrodynamic force. The changing rule of the added mass coefficient with blocking ratio is discussed in detail, and a modification approach to the current added mass coefficient calculation method is suggested. Physical experiments are conducted to validate the modification approach, and the results show that it is accurate and can be used in further study and real practice.
Article
Engineering, Marine
Golnesa Karimi-Zindashti, Ozgur Kurc
Summary: This study examines the performance of an in-house code utilizing a deterministic vortex method on the rotation of circular and square cylinders. The results show that rotational motion reduces drag forces, suppresses fluctuating forces, and increases lift forces. The code accurately predicts vortex shedding suppression and identifies the emergence of near-field wakes in the flow over rotating square cylinders.
Article
Engineering, Marine
George Dafermos, George Zaraphonitis
Summary: The survivability of damaged ships is of great importance and the regulatory framework is constantly updated. The introduction of the probabilistic damage stability framework has rationalized the assessment procedure. Flooding simulation tools can be used to investigate the dynamic response of damaged ships.
Article
Engineering, Marine
Xuyue Chen, Xu Du, Chengkai Weng, Jin Yang, Deli Gao, Dongyu Su, Gan Wang
Summary: This paper proposes a real-time drilling parameters optimization method for offshore large-scale cluster extended reach drilling based on intelligent optimization algorithm and machine learning. By establishing a ROP model with long short-term memory neurons, and combining genetic algorithm, differential evolution algorithm, and particle swarm algorithm, the method achieves real-time optimization of drilling parameters and significantly improves the ROP.
Article
Engineering, Marine
Sung-Jae Kim, Chungkuk Jin, MooHyun Kim
Summary: This study investigates the dynamic behavior of a moored submerged floating tunnel (SFT) under tsunami-like waves through numerical simulations and sensitivity tests. The results show that design parameters significantly affect the dynamics of the SFT system and mooring tensions, with shorter-duration and higher-elevation tsunamis having a greater impact.
Article
Engineering, Marine
G. Clarindo, C. Guedes Soares
Summary: Environmental contours are constructed using the Inverse-First Order Reliability Method based on return periods. The paper proposes the use of the Burr distribution to model the marginal distribution of long-term significant wave heights. The newly implemented scheme results in different environmental contours compared to the reference approach.