Brief CV of Invited Speaker:

Prof. Ming Zhao joined Western Sydney University Australia in 2011. He is currently the director of the academic program of mechanical engineering and the leader of the hydraulic research group in his university. He has published over 200 papers in top journals and received 6 research grants from Australia Research Council. Prior to joining Western Sydney University, he received his PhD degree and did his postdoctoral research at Dalian University of Technology from 1997 to 2003, and worked at the University of Western Australia University as a research assistant professor for six years from 2005 to 2011. He as supervised totally over 20 PhD students to completion and many of his PhD students are currently working as academics in local, international universities and industry.

Abstract:

A three-dimensional computational fluid dynamic (CFD) model is developed for simulating a cylindrical Oscillating Water Column (OWC) device for harvesting wave energy. The single-phase CFD model solves the Reynolds-Averaged Navier-Stokes (RANS) equations using the finite element method for simulating the wave motion and uses an aerodynamic model to simulate the flow through the air turbine. The model is implemented to simulate wave energy harvesting of a cylindrical OWC device. Through harmonic decomposition, it is found that the first harmonic wave surface elevation oscillates like a piston in the OWC chamber. However, both the amplitude and phase of the second harmonic wave surface elevation vary significantly along the wave direction in the OWC chamber, demonstrating a sloshing mode of the second harmonic. This study further proved the reduction of the capture width ratio caused by the transverse sloshing mode when the wavelength is the same as the wave flume width. The effect of the width of the wave flume on the peak CWR is found to be negligibly small when the wave flume width is three times the OWC diameter.

Matteo Diez is a Senior Research Scientist at CNR-INM, National Research Council-Institute of Marine Engineering, Rome, Italy, where he leads a research group in multidisciplinary analysis and optimization. His research focuses on simulation-based design optimization methodologies, aiming at the affordable use of high-fidelity prime-principle based solvers in ship hydrodynamics and fluid structure interaction for both deterministic and stochastic applications. He is author of more than 100 papers published in peer-reviewed international journals (including Computer Methods in Applied Mechanics and Engineering, Engineering with Computers, Ocean Engineering, Structural Multidisciplinary Optimization, Marine Structures, Applied Soft Computing, ASME Journal of Verification, Validation and Uncertainty Quantification) and international conference proceedings. He is Editorial Board Member at Nature Portfolio‘s Scientific Reports. He has been Adjunct Professor at the Università Iuav di Venezia, Università degli Studi Roma Tre, and the Istituto Nazionale di Architettura, IN/ARCH. He has been Visiting Research Scholar at the University of Iowa under ONR support. He has been co-chair and technical team member of several activities on deterministic and stochastic optimization for vehicle design within NATO Science and Technology Organization Applied Vehicle Technology Panel. He has been principal investigator of ONR-funded NICOP (Naval International Cooperative Opportunities in Science and Technology Program) grants. He received his M.Sc. degree in Mechanical Engineering from Università degli Studi Roma Tre in 2003 and his Ph.D. degree in Mechanical and Industrial Engineering from the same University in 2007, with a thesis on multidisciplinary optimization methods for conceptual aircraft design.

Abstract:

The prediction and analysis of ship behavior in heavy weather conditions are critical for ensuring operational safety and performance. This study focuses on the course-keeping performance of a free-running naval destroyer (namely the 5415M model) operating in irregular stern-quartering waves at Sea State 7, a highly challenging scenario characterized by significant wave heights and near-resonant roll conditions. Using Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations, the ship’s responses are evaluated in terms of six degrees of freedom motion and rudder actions. In this study, the URANS simulations are conducted with the CFDShip-Iowa code with a total grid size of approximately 45 million points and considering up to 132 encounter waves, resulting in significant computational costs nearing one million CPU hours. The CFD results are validated against experimental fluid dynamics (EFD) data. Key results highlight the ability of the URANS solver to accurately reproduce statistical properties of incoming waves and ship motions, including expected values, standard deviations, and probability distributions. Validation metrics confirm remarkable agreement between CFD and EFD data across most motion variables, with notable success in capturing the bi-modal roll behavior observed in experiments. The analysis emphasizes severe roll motions and capsizing events, leveraging advanced data-driven techniques to characterize motions’ coupling and identify severe events. Dynamic mode decomposition (DMD) is applied to EFD and CFD time histories, uncovering the fundamental modes of motion and correlations that govern the ship’s dynamic response in such conditions. Furthermore, the k-means clustering facilitates the identification of wave sequences that lead to severe events, enabling their deterministic reconstruction for focused analysis using regular wave computations. This process provides critical insights into the causal mechanisms behind extreme ship motions and supports the development of predictive capabilities. In addition, the study discusses data-driven modeling techniques, including DMD, feedforward neural networks (FNN), and recurrent neural networks (RNN), to enable real-time forecasting (nowcasting) of ship motions and trajectories. Here, by training on simulation data, these methods demonstrate their ability to provide short- and medium-term predictions of ship responses with good accuracy. Data-driven methods enable fast, computationally efficient predictions that can be deployed within digital twin frameworks for naval vessels, offering new opportunities for real-time monitoring, control, and optimization, enabling near real-time predictions and decision-making in high-sea states, providing critical support for operational safety and mission success.

Brief CV of Invited Speaker:

Pengnan Sun is an associate professor and doctoral supervisor at School of Ocean Engineering and Technology of Sun Yat-sen University, where he also serves as the director of the Ocean-Connect Supercomputing Center. He earned his doctoral degree from Harbin Engineering University in 2018. From 2013 to 2015, he worked at CNR-INM in Italy. Following that, he conducted postdoctoral research at École Centrale de Nantes in France from 2018 to 2020. He is recognized as one of the top 2% of research scientists globally and listed among the young talents of the Association for Science and Technology of China. In 2024, he received the Guangdong Outstanding Young Scholar Fund. His research focuses on the development of meshfree numerical methods, particularly Smoothed Particle Hydrodynamics (SPH), and the application of these methods in developing CAE software to solve fluid-structure interaction issues in ship and ocean engineering. He has published over 80 academic papers in peer-reviewed journals, including Journal of Computational Physics (JCP) and Computer Methods in Applied Mechanics and Engineering (CMAME), and has accumulated more than 3,500 citations on Google Scholar. Dr. Sun has received several academic awards, including the 2022 EABE "Best Paper Award," the 2020 SPHERIC Online "Best Presentation Award," and a High Citation Award from the Journal of Hydrodynamics. He serves on the editorial boards of six academic journals, such as the Journal of Marine Science and Application and the Journal of Hydrodynamics. Additionally, he is a member of both the steering committee and scientific committee of SPHERIC, an international organization representing the community of researchers and industrial users of SPH. In this capacity, he chaired the 2024 SPHERIC Zhuhai International Workshop, which attracted more than 180 scholars in the field to discuss the latest developments in SPH theory, numerical methods, and applications.

Abstract:

Smoothed Particle Hydrodynamics (SPH) is a mesh-free Lagrangian method adept at simulating free-surface and interfacial flows. Its capability to accurately and automatically track fluid-structure and multi-phase interfaces makes it particularly advantageous for addressing complex fluid-structure interaction (FSI) problems which often involve large deformations, moving boundaries, multi-media interactions, strong convection, and intense free-surface splashing. Over the past 30 years, significant advancements have been made in addressing common issues associated with traditional SPH models, including pressure noise, volume non-conservation, poor computational stability, challenges in simulating turbulence at high Reynolds numbers and so on. These advancements have established the mesh-free SPH method as a leading algorithm in FSI hydrodynamics. This presentation will focus on the introduction of a robust multiphase δ+-SPH model designed to tackle challenging gas-liquid-structure coupling problems. First, the historical development of SPH in hydrodynamics will be reviewed, highlighting advanced technologies that enhance simulation accuracy and stability. Following this, we will present recent developed gas-liquid-structure coupling techniques that enable the simulation of multiphase flows with high density ratios and varying compressibility. Finally, we will demonstrate extensive simulations and validations of complex gas-liquid-structure coupling scenarios, including rolling wave slamming with air cushioning effects, violent liquid tank sloshing with air bubble capture, cavitating bubbles around hydrofoils, droplet icing, water drops from air tankers in high-speed airflows and so on. The numerical results and validations will show that the advanced multiphase δ+-SPH model, enhanced with innovative numerical techniques, offers significant advantages for simulating gas-liquid-structure interactions. This model is poised to become a vital component in the future development of industrial CAE software for addressing such multiphase FSI challenges across various fields.

Keynote Presentation 7  15:45-16:30

Brief CV of Invited Speaker:

Robinson Perić is a postdoctoral researcher at the Institute for Fluid Dynamics and Ship Theory at Hamburg University of Technology. He has studied Computational Engineering (B.Sc.) at the Friedrich-Alexander University Erlangen-Nuremberg and Theoretical Mechanical Engineering (M.Sc.) at Hamburg University of Technology, both with specialization on computational fluid dynamics. He received his PhD at Hamburg University of Technology on the topic: Minimizing undesired wave reflection at the domain boundaries in flow simulations with forcing zones. His research interests center around theoretical, experimental and computational fluid dynamics, with special focus on their application to naval and ocean engineering problems. His publications include research on optimizing boundary conditions for wave-generation and wave-damping in flow simulations, interface-sharpening schemes for multiphase flows, ship maneuvering in nonlinear waves, rogue waves, extreme-wave impacts, cavitation, turbulent flows, aerodynamics and wave energy conversion. The study of ocean waves is one of his main research interests.

Abstract:

Knowledge about ocean waves is important for engineers in the maritime field, especially in ship hydrodynamics and ocean engineering. Classical investigations include computing seakeeping behavior of ships and wave loads on offshore structures, which are routinely performed during design with different tools (empirical methods, potential flow, computational fluid dynamics, etc.). Such topics are typically well covered in standard curricula for engineering students in these disciplines. However, today there is an increasing interest in nonlinear phenomena related to ocean waves. This includes investigation of ship maneuvers in realistic, short-crested seas, extreme-wave impacts on offshore structures, or the study of wave-wave interactions and wave breaking to develop improved models for weather and climate simulations. Such topics are less frequently covered in engineering curricula, partly because they are based on progress made in other disciplines. Research on ocean waves profited from developments in different fields, where it was pursued with different research interests and partly independently from each other. Therefore, the aim of this talk will be to give a brief account of the history of research on ocean waves from three perspectives: engineering, geophysics and mathematics. Main contributions from each field will be highlighted and discussed regarding their relevance for state-of-the-art ship hydrodynamics and ocean engineering. An outlook will outline the benefits from a closer collaboration between these fields.

Brief CV of Invited Speaker:

Prof. Zheng-Tong Xie (ZX) is a full Professor of Aeronautics and Astronautics at the University of Southampton (UoS), leading research in environmental and urban fluid dynamics. ZX received his academic degrees at Shanghai Jiao Tong University (1986-1995). ZX worked at the Institute of Mechanics, CAS from 1995-2000. Since 2000, he worked in the University of Surrey, and then the University of Southampton. His research interests include turbulent flow around bluff bodies, computational fluid dynamics, and fast computation in large-scale problems. ZX is the PI of several projects funded by the research councils. Currently, ZX is the PI of EPSRC funded-project FUTURE (EP/V010514/1, Jun 2021 - Jun 2024), and the PI of NERC funded-project ASSURE (NE/W002841/1, Dec 2021 - Nov 2025). ZX has published more than 50 papers. The synthetic turbulence generation method developed by ZX and his team has been implemented in the releases of several widely used CFD packages and many in-house codes worldwide, demonstrating its excellent performance for high-fidelity simulations. He is a Fellow of the Royal Meteorology Society and a Fellow of the Royal Aeronautical Society.

Abstract:

The talk reports our latest research on flows around arrays of sharp-edged cylinders with various sizes and arrangements. Key parameters analyzed include the dimensionless vortex shedding frequency (Strouhal number), and the location where individual wakes merge. Results show that for smooth and turbulent inflows in different angles of incidence, the Strouhal number, based on the freestream velocity and an effective cluster size proposed in this study, closely resembles that of an isolated square cylinder. The Strouhal number is primarily influenced by the solid portion of the array's cross-section, with minor adjustments for porosity. For turbulent inflows with an integral length scale exceeding the cluster size, the Strouhal number decreases markedly compared to smooth inflow cases, indicating a significant influence of inflow large-scale turbulence on cluster dynamics. This study demonstrates the cluster effect of an array of cylinders and proposes a simple approach to quantify this effect.

Keynote Presentation 10  18:00-18:45