Technological innovation constantly transforms and redefines the human element’s position inside complex socio-technical systems. Autonomous operations are in various phases of development and practical deployment across several transport domains, with marine operations still in their infancy. This article discusses current trends in developing autonomous vessels and some of the most recent initiatives worldwide. It also investigates the individual and combined effects of maritime autonomous surface ships (MASS) on regulations, technology, and sectors in reaction to the new marine paradigm change. Other essential topics, such as safety, security, jobs, training, and legal and ethical difficulties, are also considered to develop a solution for efficient, dependable, safe, and sustainable shipping in the near future. Finally, it is advised that holistic approaches to building the technology and regulatory framework be used and that communication and cooperation among various stakeholders based on mutual understanding are essential for the MASS to arrive in the maritime industry successfully.
Icing is a severe problem faced by wind turbines operating in cold climates. It is affected by various fluctuating parameters. Due to ice accretion, a significant drop in the aerodynamic performance of the blades’ airfoils leads to productivity loss in wind turbines. When ice accretes on airfoils, it leads to a geometry deformation that seriously increases turbulence, particularly on the airfoil suction side at high angles of attack. Modeling and simulation are indispensable tools to estimate the effect of icing on the operation of wind turbines and gain a better understanding of the phenomenon. This paper presents a numerical study to assess the effect of surface roughness distribution, along with the effect of two turbulence models on estimating wind turbine airfoils’ aerodynamic performance losses in the presence of ice. Aerodynamic parameter estimation was performed using ANSYS FLUENT, while ice accretion was simulated using ANSYS FENSAP-ICE. The results using the adopted modeling approaches and the simulation tools were compared with another numerical study and validated against experimental data. The validation process demonstrated the model’s accuracy when considering roughness distribution via the beading model available in ANSYS FENSAP-ICE. The two turbulence models examined (Spalart–Allmaras and k-ω SST) gave comparable results except for the drag at high angles of attack. The k-ω SST model was more efficient in replicating turbulence at high angles of attack, leading to higher accuracy in aerodynamic loss estimation.
Wind turbine icing has been the subject of intensive research over the past two decades, primarily focusing on applying computational fluid dynamics (CFD) to 2D airfoil simulations for parametric analysis. As a result of blades’ airfoils deformation caused by icing, wind turbines experience a considerable decrease in aerodynamic performance resulting in a substantial loss of productivity. Due to the phenomenon’s complexity and high computational costs, a fully 3D simulation of the entire iced-up rotating turbine becomes infeasible, especially when dealing with several scenarios under various operating and weather conditions. The Quasi-3D steady-state simulation is a practical alternative method to assess power loss resulting from ice accretion on wind turbine blades. To some extent, this approach has been employed in several published studies showing a capability to estimate performance degradation throughout the generation of power curves for both clean and iced wind turbines. In this paper, applying the Quasi-3D simulation method on wind turbine icing was subject to a survey and in-depth analysis based on a comprehensive literature review. The review examines the results of the vast majority of recently published studies that have addressed this approach, summarizing the findings and bringing together research in this area to conclude with clear facts and details that enhance research on the estimation of wind turbine annual power production loss due to icing.