Reduction of ship emissions using innovative surface structures to reduce friction

The motivation for this project is to assist the maritime community to reduce emissions considerably from the ships, especially ocean-going vessels, by a practical, cost effective method applicable to both new-builds and existing vessels. This can be achieved by reducing skin friction, which count for more than 70% of resistance of most ocean-going vessels. By using an innovative surface structure, which is applied with anti-fouling coating, the skin friction could be reduced up to 10%. This passive method will not require additional energy consumption (like air compressors in case of air lubrication) or any alteration to the hull structure or ship's equipment. Current studies are limited to low Reynolds numbers, which do not cover operational profile of ocean-going vessels. Therefore, novel numerical and experimental investigations will be done to analyse these structures at high Reynolds numbers. Complex computational fluid dynamic (CFD) methods will be developed which work in combination with novel experimental methods established in this project to provide reliable analyses. These methods will be applied to reliable and efficient design and optimisation of the surface structure. The developed surface structure will be tested on an ocean-going vessel. In details the project shall: -Provide an understanding of drag reduction obtained from the innovative surface structure in high Reynolds number, optimizing the pattern and shape to obtain maximum drag reduction. -Investigate the robustness of this drag reduction technology when exposed to disturbances relevant to what a ship experiences in the sea. -Provide full-scale simulation and field measurements on an entire ship. -Estimate the total emission reduction for the global ocean-going fleet. During the course of the project, experimental methods are developed to test plates with different type of surface characteristics in SINTEF Ocean's cavitation tunnel. Total longitudinal force is measured. Flow details are visualized using laser based measurement methods. On the numerical side, NTNU has performed detailed studies on small scale, while SINTEF Ocean has done numerical simulation on large scale.

The motivation for this proposal is to assist the maritime community to reduce emissions considerably from the ships, especially ocean-going vessels, by a practical, cost effective method applicable to both new-builds and existing vessels. This can be achieved by reducing skin friction, which count for more than 70% of resistance of most ocean-going vessels. By using an innovative surface structure, which is applied with anti-fouling coating, the skin friction could be reduced up to 10%. This passive method will not require additional energy consumption (like air compressors in case of air lubrication) or any alteration to the hull structure or ship's equipment. Current studies are limited to fairly low Reynolds numbers, which do not cover operational profile of ocean-going vessels. Therefore, novel numerical and experimental investigations are required to analyse these structures at high Reynolds numbers. In this project complex computational fluid dynamic methods will be developed which work in combination with novel experimental methods developed in this project to provide reliable analyses. These methods will also be applied to reliable and efficient design and optimisation of the surface structure. The developed surface structure will be tested on an ocean-going vessel. Emission savings will be calculated for the whole operational profile of the vessel. Then, an estimation of the potential saving for the global shipping will be provided. In details the project shall: -Provide an understanding of drag reduction obtained from the innovative surface structure in high Reynolds number, optimizing the pattern and shape to obtain maximum drag reduction. -Investigate the robustness of this drag reduction technology when exposed to disturbances relevant to what a ship experiences in the sea. -Provide full-scale simulation and field measurements on an entire ship. -Estimate the total emission reduction for the global ocean-going fleet.