Article
Engineering, Marine
Jinshi Liu, Junliang Gao, Huabin Shi, Jun Zang, Qian Liu
Summary: This article investigates the transient fluid motion within a narrow gap formed by two fixed boxes suffered from incident focused wave groups. The study reveals that the most dangerous place to green water is always the front edge of the two-box system.
Article
Engineering, Marine
Jiawang Liu, Bin Teng
Summary: This study investigated the ringing response of a monopile foundation to focused wave groups using a novel numerical wave tank based on the high-order spectral method. It was found that resonant behavior was excited at the triple-wave frequency of the wave loads, and the influence of the damping ratio on the ringing response was considered. Different incident wave models and hydrodynamic models were used to predict wave loads and induced responses over different wave steepness, with the wavelet transform successfully revealing local characteristics of the wave loads and ringing response.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2021)
Article
Engineering, Marine
Ke Qu, Yancheng Lie, Xu Wang, Xiaohan Li
Summary: During severe weather, coastal facilities are at risk of extensive damages and loss of life due to surges and waves. This study investigates the potential of coastal vegetation in attenuating wave runup and protecting coastal communities from flooding and land loss. The presence of emergent vegetation patches is found to dissipate wave energy and reduce the maximum wave runup heights at sloped beaches. The research findings could contribute to the design of coastal soft protection measures.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Mechanics
Hao Chen, Ling Qian, Deping Cao
Summary: This paper presents a numerical investigation on the harmonic structure of hydrodynamic forces on a fixed and simplified representative floating production, storage and offloading (FPSO) vessel hull under dispersive phase-focused wave groups. The numerical model suggests that the non-dimensional inline force of an FPSO remains similar in terms of temporal development under different wave steepness. The harmonic structure of the inline force is weakly dependent on wave steepness and bow diameter, but strongly dependent on the FPSO length.
Article
Engineering, Marine
K. Qu, J. X. Huang, L. Guo, X. H. Li
Summary: Extreme waves pose a threat to coastal regions, leading to the construction of coastal defense structures. However, there is a lack of research on the hydrodynamic characteristics of submerged permeable breakwaters under extreme wave conditions.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2022)
Article
Engineering, Civil
Jun-liang Gao, Jing Lyu, Jian Zhang, Jun Zang
Summary: This study investigates the hydrodynamic characteristics of gap resonance in a narrow gap formed by two adjacent boxes, revealing the significant effects of releasing the heave degree of freedom of the lee-side box on resonance features, including increased fluid resonant period and decreased wave amplification factor.
CHINA OCEAN ENGINEERING
(2023)
Article
Geochemistry & Geophysics
Ehsan Moradian Bajestani, Anooshiravan Ansari, Ehsan Karkooti
Summary: A model for frequency-dependent local and regional P-wave attenuation in continental paths in the Iranian Plateau is estimated, showing three distinct sections of attenuation and faster attenuation of P-wave amplitude compared to global models at local distances.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Acoustics
Feilong Li, Fangxin Zou
Summary: A 2D hybrid spectral/finite element scheme is proposed for numerically resolving crack induced contact acoustic nonlinearity in solid structures. The method effectively reduces degrees of freedom while ensuring high numerical accuracy, demonstrating high convergence rate in ultrasonic wave propagation modeling and capability to converge for weak crack-induced contact acoustic nonlinearity.
JOURNAL OF SOUND AND VIBRATION
(2021)
Article
Energy & Fuels
Harry B. Bingham, Yi-Hsiang Yu, Kim Nielsen, Thanh Toan Tran, Kyong-Hwan Kim, Sewan Park, Keyyong Hong, Hafiz Ahsan Said, Thomas Kelly, John V. Ringwood, Robert W. Read, Edward Ransley, Scott Brown, Deborah Greaves
Summary: This paper presents an ongoing international effort to establish numerical modeling guidelines for wave energy converters, focusing on point absorbers and breakwater-mounted Oscillating Water Column (OWC) devices. The study compares experimental and numerical results, highlighting the importance of reducing uncertainties in future experiments to draw firm conclusions about the accuracy of the numerical models.
Article
Computer Science, Interdisciplinary Applications
Yanlin Shao, Zhiping Zheng, Hui Liang, Jikang Chen
Summary: The paper proposes an alternative formulation based on a non-inertial coordinate system that allows for large-amplitude horizontal motions in floating offshore structures. New explicit time-integration methods and optimized low-pass filters are used to solve the problems, which are applicable to engineering fields dealing with similar mathematical problems. The model is considered a complete second-order wave-load model that solves all second-order wave loads simultaneously.
COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING
(2022)
Article
Nanoscience & Nanotechnology
Delin Wu, Shenping Gao, Jian Li, Lei Yao, Xingyan Yu, Zhikai Zhang, Hengda Zhang, Xiaobo Wang
Summary: This study investigates the amplitude and phase relation of harmonics in nonlinear focused ultrasound through numerical simulations and measurements. The results show that as the source pressure increases, the focusing gain for the fundamental component tends to decrease while the focusing gains for the second and third harmonics rise, with little change in relative phases.
Article
Engineering, Marine
Dezhi Ning, Chen Liang, Lifen Chen, Chongwei Zhang
Summary: This study investigates the propagation and evolution of wave focusing on a sloping bed using a two-dimensional fully nonlinear numerical model. The results show that the focused wave crest decreases and the actual focal location shifts with an increase in bed slope. When the initial focusing position is pre-set at the beginning of the slope, the free surface elevations and wave energy of higher-order harmonics on the slope are smaller than on a flat bottom. However, when the focusing position is pre-set at the back part of the slope, the conclusions are opposite, indicating that the slope facilitates energy conversion from low frequencies to high frequencies.
Article
Nanoscience & Nanotechnology
Delin Wu, Shenping Gao, Jian Li, Lei Yao, Xingyan Yu, Zhikai Zhang, Hengda Zhang, Xiaobo Wang
Summary: When studying nonlinear focused ultrasound, the amplitude and phase relation of harmonics are crucial for understanding focusing gain. With increasing source pressure, different harmonics show varying trends in focusing gain, while the relative phase remains relatively stable.
Article
Engineering, Electrical & Electronic
Jintao Wang, Xiaohui Zhang, Xu Shi, Jian Song
Summary: In the new 5G era, millimeter wave communications can achieve huge data rate growth and wide bandwidth with a hybrid precoding architecture, effectively optimizing the system's spectral efficiency through the design of digital and analog precoders. The use of index modulation (IM) techniques can further improve spectral efficiency in mmWave systems. Simulation results demonstrate that IM-aided systems outperform traditional mmWave systems, making IM a promising technique for practical SE-driven mmWave systems.
IEEE COMMUNICATIONS MAGAZINE
(2021)
Article
Engineering, Marine
Mohammad Adibzade, Hassan Akbari
Summary: This study presents a novel approach for evaluating Multi-Body Floating Wave Energy Converters (MBFWEC) operating in complex sea states. The approach utilizes a developed Transfer Function (TF) and is applied to wave data measured at the northern coast of the Oman Sea. The results demonstrate its accuracy and applicability for evaluating and tuning FWEC devices in regions with complex sea states.
Article
Acoustics
Finnur Pind, Cheol-Ho Jeong, Jan S. Hesthaven, Allan P. Engsig-Karup, Jakob Stromann-Andersen
Summary: The paper presents a phenomenological method for modeling angle dependent surface impedance properties in time-domain wave-based simulations, which improves accuracy with little computational cost.
Article
Energy & Fuels
Morten Bech Kramer, Jacob Andersen, Sarah Thomas, Flemming Buus Bendixen, Harry Bingham, Robert Read, Nikolaj Holk, Edward Ransley, Scott Brown, Yi-Hsiang Yu, Thanh Toan Tran, Josh Davidson, Csaba Horvath, Carl-Erik Janson, Kim Nielsen, Claes Eskilsson
Summary: Highly accurate and precise heave decay tests were conducted on a 300 mm diameter sphere in a meticulously designed test setup at Aalborg University, Denmark, aiming to provide a rigorous benchmark dataset for numerical model validation. The results showed a high correlation between physical and numerical test results, making the physical test results very suitable for numerical model validation.
Article
Engineering, Ocean
Jacob B. H. Hicks, Harry B. Bingham, Robert W. Read, Allan P. Engsig-Karup
Summary: This paper investigates the optimization of second-order control signals for producing stable non-linear deep-water waves using a wedge-shaped wave generator. Both numerical and experimental methods are utilized, with the results demonstrating the applicability of the optimization procedure and the suitability of the heaving wedge for generating stable nonlinear deep-water waves.
APPLIED OCEAN RESEARCH
(2021)
Article
Engineering, Civil
V Sriram, Shagun Agarwal, Shiqiang Yan, Zhihua Xie, Shaswat Saincher, Torsten Schlurmann, Qingwei Ma, Thorsten Stoesser, Yuan Zhuang, Bo Han, Weiwen Zhao, Xiaotong Yang, Z. Li, Decheng Wan, Yi Zhang, Bin Teng, Dezhi Ning, Ningbo Zhang, Xing Zheng, Guochun Xu, Jiaye Gong, Yunbo Li, Kangping Liao, Wenyan Duan, Ronggui Hann, Windiman Asnim, Zana Sulaiman, Zhongbing Zhou, Jianmin Qin, Yucheng Li, Zhiwei Song, Xiaofan Lou, Lin Lu, Changfu Yuan, Yuxiang Ma, Congfang Ai, Guohai Dong, Hanbing Sun, Qiang Wang, Zhi-Tao Zhai, Yan-Lin Shao, Zaibin Lin, Ling Qian, Wei Bai, Zhihua Ma, Pablo Higuera, Eugeny Buldakov, Dimitris Stagonas, Santiago Martelo Lopez, Aristos Christou, Pengzhi Lin, Yanyan Li, Jinshu Lu, Sa Young Hong, Yoon-Jin Ha, Kyong-Hwan Kim, Seok-Kyu Cho, Dong-Min Park, Wojciech Laskowski, Claes Eskilsson, Mario Ricchiuto, Allan P. Engsig-Karup, Lin Cheng, Jinhai Zheng, Hanbin Gu, Guangnian Li
Summary: This paper presents a comparative study on the interaction between focused waves and a fixed cylinder, using 20 numerical solvers developed by various universities. The qualitative and quantitative comparisons based on wave probe and pressure probe time histories and spectral components show differences among different solvers. The relative error analysis indicates variations in performance among the solvers, providing insights for industrial applications.
INTERNATIONAL JOURNAL OF OFFSHORE AND POLAR ENGINEERING
(2021)
Article
Computer Science, Interdisciplinary Applications
Allan P. Engsig-Karup, Wojciech L. Laskowski
Summary: In this study, a fully nonlinear potential flow model discretized using a Galerkin spectral element method is developed for efficiently simulating unsteady water waves and their interaction with bodies in marine offshore engineering. An O(n)-scalable computational procedure based on geometric p-multigrid is proposed for solving the Laplace problem, showing improved efficiency in numerical simulations. Results demonstrate that using iterative geometric p-multigrid methods can significantly enhance the runtime efficiency of FNPF simulators.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS
(2021)
Article
Green & Sustainable Science & Technology
Adi Kurniawan, Thanh Toan Tran, Scott A. Brown, Claes Eskilsson, Jana Orszaghova, Deborah Greaves
Summary: This paper presents a computationally efficient way of simulating parametric resonance in point absorbers based on linear potential theory, which is able to simulate pitch parametric resonance with reasonable accuracy and is two orders of magnitude faster than real time on a standard computer.
IET RENEWABLE POWER GENERATION
(2021)
Article
Acoustics
Hermes Sampedro Llopis, Allan P. Engsig-Karup, Cheol-Ho Jeong, Finnur Pind, Jan S. Hesthaven
Summary: This paper presents a computational efficient and accurate method for room acoustic simulations using a reduced basis method. By solving the problem in a low-dimensional subspace for parametrized boundary conditions, the computational burden is significantly reduced. The use of the Laplace domain ensures the stability of the model. Experimental results show that this method achieves significant speedups compared to traditional methods.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2022)
Article
Engineering, Environmental
Rocco Palmitessa, Morten Grum, Allan Peter Engsig-Karup, Roland Lowe
Summary: This study proposes a physics-guided machine learning approach for fast and accurate surrogate modelling of urban drainage system hydraulics. It significantly reduces simulation times compared to traditional HiFi models while preserving a high level of model detail.
Article
Computer Science, Interdisciplinary Applications
Jens Visbech, Allan P. Engsig-Karup, Harry B. Bingham
Summary: This study presents a scalable two-dimensional Galerkin spectral element method for solving the radiation problem in linearized potential flow induced by waves on a floating offshore structure. The method shows excellent agreement with known benchmark results and demonstrates high accuracy and efficiency.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS
(2023)
Article
Energy & Fuels
Claes Eskilsson, Johannes Palm
Summary: This study presents two recent developments in high-fidelity wave-body-mooring (WBM) modeling, including a new fluid-mooring coupling method and support for inter-moored multibody simulations. Experimental tests verify the accuracy of the fluid-mooring coupling, and the model performs well in predicting the actual response of a floating offshore wind turbine.
JOURNAL OF OCEAN ENGINEERING AND MARINE ENERGY
(2022)
Article
Engineering, Marine
Eirini Katsidoniotaki, Zahra Shahroozi, Claes Eskilsson, Johannes Palm, Jens Engstrom, Malin Goteman
Summary: The study develops a high-fidelity CFD model for wave energy converters and validates it using experimental data. The model is able to accurately simulate the system under extreme wave conditions. A new methodology for handling mesh deformation in CFD codes is also successfully applied and validated.
Article
Acoustics
Hermes Sampedro Llopis, Cheol-Ho Jeong, Allan P. Engsig-Karup
Summary: Quick simulations using the reduced basis method (RBM) are essential for finding optimal acoustic conditions in building design. RBM enables quick evaluations of changing absorption materials for different surfaces in room acoustic simulations with inhomogeneous properties. This study investigates the application of RBM in various geometries and inhomogeneous surface absorption with significant speedup compared to high fidelity numerical solver.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2023)
Proceedings Paper
Automation & Control Systems
Morten Ryberg Wahlgreen, Kristian Meyer, Tobias K. S. Ritschel, Allan Peter Engsig-Karup, Krist Gernaey, John Bagterp Jorgensen
Summary: In this study, a numerical case study is presented to model and simulate the upstream and downstream processes of monoclonal antibody (mAb) production. A systematic and intuitive modeling methodology is applied to the existing upstream and downstream processes. The resulting models are based on differential mass balances and kinetic expressions for reactions and adsorption. The simulation model, coupling the upstream and downstream processes, serves as a benchmark for numerical estimation, control, and optimization studies.
Article
Mathematical & Computational Biology
Bjorn C. S. Jensen, Allan P. Engsig-Karup, Kim Knudsen
Summary: The use of epidemic modelling and predictions is crucial for understanding disease dynamics and making informed decisions. This study proposes the use of the generalized Polynomial Chaos framework for efficient uncertainty quantification in compartmental epidemic models. The results of two case studies based on Danish Covid-19 data demonstrate the applicability and efficiency of this technique for uncertainty quantification in epidemic modelling.
MATHEMATICAL MODELLING OF NATURAL PHENOMENA
(2022)
