EMShip Week 28-30 October 2025 in Nantes, France
The related staffs: Deniz Bayraktar Bural & Ceren Bilgin Güney
Six thesis proposals were submitted from our faculty, and these proposals were presented in detail. In addition, information about ITU and the facilities offered by our faculty was introduced. Contributions were also made to the thesis proposal presentations overall, and collaboration between academia and industry was strengthened through organized meetings where industry partners introduced themselves, proposed thesis topics, and offered internship opportunities. These activities provided EMShip students with valuable practical experience and supported successful career development in ship, marine, and offshore engineering.
A Hybrid CFD and Potential Flow Motion Analysis of Spar Buoys with Damping-Enhanced Appendages
The related staffs: Deniz Bayraktar Bural, Murtala Nyako Musa
This study investigates the hydrodynamic response of a spar-type buoy equipped with a solid, perforated, and novel corrugated plate appendage introduced here for the first time to enhance motion damping. A hybrid approach combining time-domain CFD simulations and frequency-domain potential-flow analysis was employed, providing a framework to incorporate viscous effects that are often omitted in potential-flow models. In the first stage, free-decay simulations were carried out in ANSYS Fluent for a baseline spar and three appendage-equipped configurations. The resulting heave and pitch decay responses were analyzed to determine natural frequencies and viscous damping coefficients. Prior to that, the CFD solver was validated and verified against published experimental data, confirming the reliability of the numerical setup. In the second stage, frequency-domain hydrodynamic diffraction analysis was conducted in ANSYS AQWA, and the CFD-derived viscous damping coefficients were incorporated into the potential-flow model to improve motion predictions near resonance. The comparison between RAOs with and without viscous damping indicated reductions of approximately 55–62% in heave and 41–60% in pitch at resonance, with the perforated plate consistently yielding the highest damping and lowest RAO peaks. This work introduces the first corrugated plate appendage design for spar buoys and establishes a validated CFD–potential-flow hybrid framework that enables more realistic motion predictions and provides practical design guidance for damping-enhanced spar buoys in offshore energy applications.
Numerical Investigation of Wave Induced Scour Depth Around Slender and Grouped Monopile
The related staffs: Deniz Bayraktar Bural, Bekir Sürücü
Wave-induced scour around monopile foundations poses a critical challenge for offshore wind turbine design, affecting stability, serviceability, and maintenance costs. Despite extensive experimental studies, high-fidelity numerical tools are still needed to capture complex interactions between wave kinematics, sediment transport, and pile geometry. This study presents a numerical investigation of scour depth around slender monopiles under regular wave conditions. A validated three-dimensional CFD model (FLOW-3D) employing the Volume of Fluid method and RNG k–ε turbulence closure was used to simulate wave–structure–seabed interaction. Sediment transport was modeled using the Meyer–Peter and Müller bedload formulation and an advection–diffusion equation for suspended load. The influence of the Keulegan–Carpenter (KC) number was examined for KC = 8.8–24, covering inertia- and drag-dominated regimes. Results showed that higher KC values intensified vortex-induced sediment transport and scour, while lower KC values led to gradual development. A marked increase occurred beyond KC ≈ 14, indicating a regime shift in flow–sediment interaction. Grouped-cylinder cases at G/D = 1 and 2 showed that narrow spacing produced mutual sheltering and reduced scour, whereas wider spacing caused deeper localized erosion. Single monopile predictions matched experimental data and empirical formulas, demonstrating the model's predictive capability. These findings emphasize the strong KC dependence of scour and suggest that spacing ratios above G/D = 1.5 may help mitigate adverse group effects in array layouts under oscillatory wave forcing.
Wave-Induced Force Modeling on a Monopile Foundation at Gökçeada Using Spectral and Diffraction-Based Approaches
The related staffs: Deniz Bayraktar Bural
This study presents a numerical framework to reconstruct long-term wave-induced force histories on monopile foundations supporting offshore wind turbines in data-limited, fetch-limited marine environments. The methodology is demonstrated for the northeastern Aegean Sea near Gökçeada, where in-situ wave measurements are limited or not readily available. The objective is to model the wave-induced forces acting on offshore monopile-supported wind turbines under irregular sea states. By combining site-specific spectral wave data with diffraction-based force estimation, the study provides a detailed assessment of hydrodynamic load contributions across the frequency domain, offering critical insights for offshore wind energy infrastructure in the Northern Aegean Sea. A site-specific JONSWAP spectrum is constructed using a 10-year reanalysis dataset to characterize the local sea state. Wave loading on the monopile is estimated using MacCamy-Fuchs diffraction theory, which captures frequency-dependent hydrodynamic effects for large-diameter cylindrical structures. To ensure theoretical consistency, spectral components outside the applicable range are excluded with minimal energy loss. The resulting force spectrum is transformed into the time domain using inverse Fourier techniques with randomized phase, yielding a representative wave force signal for time-domain analysis. To assess extreme loading conditions, a statistical extreme value analysis is performed using threshold-based fitting. The proposed framework enables realistic wave load simulation in coastal regions lacking field measurements and supports applications such as fatigue assessment, reliability analysis, and offshore wind turbine design in semi-enclosed seas.
