Applications of bubble curtains in marine oil spill containment: Hydrodynamic characteristics, applications, and future perspectives

Research on the oil retention effect of pneumatic oil barriers under current and wave action

The pneumatic oil barrier is a novel device that intercepts oil spills by releasing high-pressure gas underwater to form a curtain of bubbles. However, its performance can be affected by both internal factors and external influences like water flow and waves, leading to varying degrees of oil interception failure and reduced effectiveness. This study combines physical experiments with numerical simulations to analyze the impact of nozzle parameters, arrangement, flow velocity, and wave effects on oil interception loss and effective containment distance under uniform flow and wave conditions. The findings establish relationships between these factors and interception efficiency, revealing reasons for changes in effective containment distance through flow field analysis. The research indicates that the pneumatic oil barrier is effective for floating oil with flow velocities below 0.15 m/s; the optimal nozzle diameter is 1.5 mm, as increasing it affects the stability of horizontal flow and oil layers. Additionally, a dual-pipe arrangement produces a wider and more stable horizontal flow on the water surface, enhancing oil interception effectiveness, while waves can destabilize oil layers, reducing effective containment distance.

Ultra-Durable, Internally Self-Sliding Superhydrophobic Coating for Underwater Protection Performance Evaluation

Developing highly durable coatings, endowing comprehensive protection capabilities of antifouling, drag reduction, and corrosion resistance in underwater settings, holds paramount significance for modern maritime undertakings. However, the inferior multifunctional compatibility and weak structural strength have proven to pose an extremely formidable challenge. Herein, this study reports an internally self-sliding coating that imparts liquid-repellence and ion permeation resistance without the necessity of a complex fabrication process. The key lies in combining integrated structure-function strategy with particle close-packing method of fluorine-grafted layered silicate particles. These particles demonstrate and exhibit a unique self-sliding property due to the weak van der Waals forces between the lamellae from the typical layered crystal structure. The durability and underwater protection of these coatings are clearly demonstrated by their outstanding mechanical wear resistance, a drag reduction efficiency of up to 25%, and the capacity to remain corrosion-free in saltwater for over 1000 h. Owing to the slippery frictional action and the closely packed surface microstructure, the coating demonstrates outstanding long-term stability and anti-permeability properties. This strategy offers a universal design framework for engineering ultra-durable coatings applicable to a diverse range of underwater comprehensive protection applications.

Numerical and experimental simulation on efficiency of air bubble barrier on various pollutants for preventing oil spill spread

This study conducts experimental and numerical simulations and analyzes the effects of the air bubble barrier (ABB) on the oil spill spread prevention efficiency regarding the varying aperture diameter, air discharge, and pollutant type. In a computational fluid dynamics simulation, a multiphase flow is studied using the finite volume method with the volume of fluid technique in the Star CCM+ software. The pipe generating air bubbles is fixed at the bottom of the tank at 1.8 m from the side of the experimental setup. The distinctive points of the study are the experiments conducted on different pollutants and the utilization of a novel adjustable air nozzle positioned on the air feed pipe. The effectiveness of the ABB in mitigating the spread of marine pollution is contingent on the aperture size, air discharge, and pollutant type. This study demonstrates that the ABB's feasibility for preventing the oil spill spread has improved.