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Dr Vasily Kostikov, Assistant Professor at Xi’an Jiaotong–Liverpool University, will present the seminar titled "Green-Naghdi theory in application to the problems of hydroelasticity."

When: 11/02/2026 from 4.00 PM to 5.00 PM

Where: E1-L1-MR204, SIT Punggol

Abstract: The Green-Naghdi theory was originally developed by A.E. Green of the University of Oxford and P.M. Naghdi of the University of California to study wave-structure interaction. In contrast to the classical perturbation approach to long-wave equations, the Green-Naghdi theory draws on the theory of directed fluid sheets, which has roots in the theory of shells and plates in structural mechanics, and on a three-dimensional continuum model called a Cosserat surface. This approach yields a set of partial differential equations for the continuum under study that represent the conservation of mass and integrated momentum and satisfy the nonlinear boundary conditions exactly. The Green-Naghdi equations are classified by the number of functions that prescribe the distribution of vertical velocity across the fluid depth. Since no perturbation or scaling parameters are used in the derivation of these equations, there is no theoretical restriction on the limit to which the theory is applicable. In my presentation, I will discuss the development of analytical and numerical models for the interaction of nonlinear waves with floating and submerged deformable plates in the context of the Level I Green-Naghdi theory. Since the motion and deformation of an elastic structure also modify the flow field, a comprehensive analysis of hydroelasticity problems requires simultaneous consideration of two-way fluid-structure and structure-fluid interactions. This challenge is addressed by coupling the Green-Naghdi theory with appropriate structural elasticity equations. As a result, an accurate and efficient numerical model is developed to predict the hydroelastic response of floating and submerged deformable structures (e.g., floating solar panels, ice sheets in marginal ice zones, muddy seafloor, underwater tunnels, and wave breakers).

Short Bio of Speaker: Vasily Kostikov is an Assistant Professor at Xi’an Jiaotong–Liverpool University. He graduated from Novosibirsk State University (Russia) in 2010 and obtained his PhD from Lavrentyev’s Institute of Hydrodynamics (Novosibirsk, Russia) in 2013. He is an expert in asymptotic methods in fluid mechanics and focuses on theoretical and numerical modelling of nonlinear problems. His research is concerned with theoretical and numerical modelling. The topics of his study include the propagation of water waves and the interaction of waves with floating and submerged elastic structures.

Zhenye Lu, PhD candidate in Marine Technology and Engineering at Zhejiang University, will present the seminar titled "Hydrodynamic analysis of a multi-arc composite breakwater under wave action." 

When: 04/05/2026 from 3.00 PM to 4.00 PM

Where: TBD

Abstract: This study presents a semi-analytical model for wave scattering by a multi-arc composite breakwater consisting of concentric, thin-walled, bottom-mounted arcs that may be impermeable or porous. Based on linear potential flow theory, the eigenfunction matching method and Galerkin expansion are employed to solve the hydrodynamic problem, with convergence and validation confirmed against published data. The analysis reveals two primary resonance mechanisms: circumferential resonance along the arcs, governed by opening angle, and radial resonance within annular gaps, sensitive to spacing. Parametric results demonstrate that the multi-arc configuration offers superior core-region protection and wave attenuation compared to single- or double-layer designs. A fully perforated arrangement minimises overall wave loads and suppresses internal wave amplification, while oblique incidence can magnify forces on inner arcs. This work provides critical theoretical guidance for the design of modular, eco-friendly arc-shaped breakwaters in coastal engineering.

Short Bio of Speaker: Zhenye Lu is a PhD candidate in Marine Technology and Engineering at Zhejiang University. His research interests lie in the interaction between water waves and offshore structures. His recent work focuses on the hydrodynamic performance analysis of multi-arc nested perforated breakwaters under wave action. Based on linear potential flow theory, he established a dynamic analysis model using the eigenfunction expansion and Galerkin methods, systematically evaluated the structural performance of the breakwater, and conducted an in-depth analysis of the resonant phenomena within the structure.

Haojie Zheng, PhD candidate in Marine Technology and Engineering at Zhejiang University, will present the seminar titled "Blade icing characteristics and dynamic response analysis of floating offshore wind turbine in cold marine environments." 

When: 04/05/2026 from 4.00 PM to 5.00 PM

Where: TBD

Abstract: Floating offshore wind turbines (FOWTs) operating in cold marine environments must confront atmospheric icing. The study aims to investigate blade icing characteristics during operation and the FOWT's dynamic response to icing. Blade icing is simulated under various operating conditions using the IEA Wind 15 MW reference wind turbine. The Computational Fluid Dynamics (CFD) methodology is used to calculate the aerodynamic performance of the icing airfoil. A fully coupled dynamic analysis of the wind turbine is performed in OpenFAST to assess the response of the FOWT after blade icing. The calculation results indicate that the wind turbine’s operating regions significantly impact ice accretion. Blade icing reduces the aerodynamic performance, leading to power generation loss. Due to different control strategies, the wind turbine’s response to blade icing differs before and after the rated wind speed. When the rated wind speed is exceeded, a reduction in pitch angle due to blade icing may lead to structural overload. Under imbalanced icing, the wind turbine’s power generation fluctuates. This study provides a reference for evaluating FOWTs in cold marine environments with respect to power generation and safety under atmospheric icing conditions.

Short Bio of Speaker: Haojie Zheng is a doctoral candidate in Marine Technology and Engineering at Zhejiang University. His research focuses on the dynamic response of floating offshore wind turbines (FOWTs) to severe icing in cold environments. To investigate atmospheric icing, he conducts numerical simulations of blade ice accretion and implements them within a fully coupled wind turbine dynamic simulation framework. For sea ice-structure interactions, he develops semi-analytical models to evaluate both rigid and elastic ice conditions. These models effectively capture the hydrodynamic phenomena of single Spar cylinders and multi-body arrays. He is dedicated to bridging rigorous mathematical modelling and practical offshore engineering challenges and is actively seeking international collaborative research opportunities in polar marine technology.