Margaret Mary Stack

The ongoing depletion of global fossil fuel resources and greenhouse effect of harmful emissions have made the development of renewable energy a universal priority. Tidal energy is one of the renewable energy sources that offers a viable alternative. However, one of the primary challenges in tidal turbine applications is the erosion of turbine blades caused by challenging marine environmental conditions. This study investigates the erosion behaviour of glass fibre-reinforced polymer (GFRP) in sea water conditions over an extended pre-exposure period of 183 days (4380 h). To achieve this, a custom-designed slurry erosion impingement rig was developed and is detailed in this paper. The results reveal significant changes in the erosion mechanisms of GFRP as a function of prolonged pre-exposure, with critical implications for the suitability of the material in tidal turbine blades for tidal energy applications. Advanced characterisation techniques, including erosion wastage maps, micro-profiling, and SEM, were employed to analyse surface degradation and erosion patterns. These tools provide insight into material performance and support the optimisation of GFRP for reliable, long-term operation in tidal energy environments. Graphical Abstract

Rain erosion testing of wind turbine blade coatings is still based almost entirely on kinetic test parameters while ignoring the temperature–salinity domains that control field damage. This short communication quantifies how far current rain erosion test conditions diverge from offshore environmental temperature–salinity envelopes. Using seas surface climatology for four offshore regions (North Sea, US Atlantic shelf, Taiwan Strait–South China Sea, Bass Strait) and temperature and water composition parameters from 11 water-based erosion studies, we show the environmental sea surface temperature (SST) spans 5 – 17 °C in the North Sea and 8 – 24 °C in the US Atlantic, rising to 20 – 32 °C in the Asia–Pacific and Bass Strait, with sea surface salinity (SSS) typically 31 – 35.5 PSU. In contrast, all reported droplet erosion tests were run between 18 and 29 °C; three of 11 used only freshwater (~ 0 PSU) and the remainder a single seawater-like level (3.0 – 3.5% NaCl, ≈30 – 35 PSU). No study combined marine salinity with cold (<10 °C) or tropical (≥28 – 30 °C) temperatures, despite evidence of markedly higher damage in saline media and up to an order of magnitude increase in polyurethane rates near the glass transition region.

Raindrop erosion of wind turbine blades’ leading edge is a critical degradation mechanism limiting wind turbine blade lifetime and aerodynamic efficiency. Protective coatings have been extensively studied to mitigate this damage. This review critically synthesises current knowledge on coating-based protection strategies against erosion, with emphasis on (i) the underlying mechanisms of erosion, (ii) advances in conventional and emerging coating technologies, and (iii) experimental approaches for testing and lifetime prediction. Across reported studies, nanofiller reinforcement (e.g., CNTs, graphene, CeO₂, Al₂O₃) enhances erosion resistance by 60–99%, primarily through improved toughness and stress-wave dissipation. Hybrid and multifunctional systems further combine mechanical durability with self-healing or anti-icing capabilities. Experimental results confirm that erosion rate follows a power-law dependence on impact velocity, with maximum damage occurring between 45° and 60° impact angles. Softer elastomeric coatings demonstrate longer incubation periods and superior viscoelastic recovery compared with rigid sol–gel systems. Persistent gaps include the lack of standardised testing, poor field–lab correlation, and limited long-term durability data. Future work should focus on coordinating multi-stressor testing with variable-frequency rain setups to replicate real field conditions and enable reliable lifetime prediction of next-generation erosion-resistant coatings.

Raindrop erosion of wind turbine blades leading edge is a critical degradation mechanism limiting wind turbine blade lifetime and aerodynamic efficiency. Protective coatings have been extensively studied to mitigate this damage. This review critically synthesises current knowledge on coating-based protection strategies against erosion, with emphasis on (i) the underlying mechanisms of erosion, (ii) advances in conventional and emerging coating technologies, and (iii) experimental approaches for testing and lifetime prediction. Across reported studies, nanofiller reinforcement (e.g., CNTs, graphene, CeO2, Al2O3) enhances erosion resistance by 60 – 99 %, primarily through improved toughness and stress-wave dissipation. Hybrid and multifunctional systems further combine mechanical durability with self-healing or anti-icing capabilities. Experimental results confirm that erosion rate follows a power-law dependence on impact velocity, with maximum damage occurring between 45 ° to 60 ° impact angles. Softer elastomeric coatings demonstrate longer incubation periods and superior viscoelastic recovery compared with rigid sol-gel systems. Persistent gaps include the lack of standardised testing, poor field-lab correlation, and limited long-term durability data. Future work should focus on coordinating multi-stressor testing with variable-frequency rain setups to replicate real field conditions and enable reliable lifetime prediction of next-generation erosion-resistant coatings.

The ongoing depletion of global fossil fuel resources and the intensification of the greenhouse effect have made the development of renewable energy a universally prioritised objective. Tidal energy is one of the renewable energy sources that offers a viable alternative due to its excellent predictability, high energy density, and long-term stability. However, one of the primary challenges in tidal turbine applications is the erosion of turbine blades caused by challenging marine environmental conditions. This study investigates the erosion behaviour of glass fibre-reinforced polymer (GFRP) in aquatic conditions over an extended pre-exposure period of 183 days (4,380 hours). To achieve this, a custom-designed slurry erosion impingement rig was developed and is detailed in this paper. The results reveal serious changes in the erosive mechanisms of GFRP as a function of prolonged pre-exposure, with critical implications for the suitability of the material in tidal turbine blades for tidal energy applications. Advanced characterisation techniques, including erosion wastage maps, micro-profiling, and SEM, were employed to analyse surface degradation and erosion patterns. These tools provide insight into material performance and support the optimisation of GFRP for reliable, long-term operation in tidal energy environments.

The tribological mechanisms of potential composite materials that could be used in tidal turbines considered the effects of various erosion parameters on the degradation modes, both with and without particles, in still and seawater conditions. The aim of this study was to investigate the potential of a specialised epoxy erosion-resistant coating for glass fibre-reinforced plastic (GFRP) in resisting the impact of slurry erosion. Slurry erosion is a process by which solid particles suspended in a fluid medium impinge on a surface, causing material loss due to repeated impacts. The coating efficacy was evaluated through a series of tests, including three different speeds and six different impinging angles and the results were used to generate tidal turbine maps. The study provided insights into the durability and of the epoxy and potential use of the coating in tidal turbine blade industries where resistance to erosion is crucial for long-term performance and safety.

Tidal energy, with its potential to provide a consistent energy output and reduce carbon emissions, has garnered significant interest. This study, which evaluates the performance of tidal turbine blades in seawater conditions and with sand particles, presents a novel approach. A slurry rig was developed to examine composite materials, and a glass fibre-reinforcement polymeric material was tested over a range of particle sizes, velocities, and impact angles. In addition, this paper used a new test protocol with 14 days (336 h) and 91 days (2184 h) of pre-exposure time of materials before testing. The results, which show significant changes in the erosive mechanisms of GFRP in short- and long-term pre-exposure time as a function of these variables, have profound implications for the design and performance of tidal turbine blades. The study also utilised scanning electron microscopy (SEM), depth profiling analysis, and erosion mapping techniques to compare the erosion behaviours of GFRP. These tools can be used to optimise such materials in tidal turbine conditions.

Tidal energy, with its potential to provide a consistent energy output and reduce carbon emis-sions, has garnered significant interest. This study, which is the first to evaluate the performance of tidal turbines in seawater conditions involving sand particles, presents a novel approach. A slurry rig was developed to examine composite materials, and a glass fibre reinforcement poly-meric material was tested over a range of particle size, velocity, impact angle, and exposure time. The results, which show significant changes in the mass loss materials as a function of these variables, have profound implications for the design and performance of tidal turbines. The study also utilized a scanning electron microscope (SEM) and depth profiling analysis, and erosion maps were generated to demonstrate the changes in erosion mechanisms. These tools can be used to optimize such materials in tidal turbine conditions.

This paper investigates the effects that rain drop erosion has on the integrity of wind turbine materials. This research involves analysis of impact models and theoretical equations to simulate the impact phenomena when a raindrop collides with a wind turbine blade at high speed. Impact phenomena that occur when a raindrop impacts with a wind turbine blade were evaluated. Additionally, the use of various types of software was considered to simulate this impact event. The model results of the raindrop impact with respect to a comparison of the governing equations and impact behaviour are addressed. Future work is outlined including adding variables to the erosion modelling algorithms.