Estimation of full-scale performance of energy-saving devices using Boundary Layer Similarity model

Abstract

The recent global trend toward decarbonization is also occurring in the maritime industry and there is an urgent need to improve the fuel efficiency of ships. Various energy-saving devices (ESDs) are adopted for this purpose. However, because of the difference in the boundary layer thickness between full-scale and model-scale, it is difficult to estimate the actual performance of ESDs in a tank test. As a solution to overcome this difficulty, the Boundary Layer Similarity model (BLS model) is proposed in which only the stern part of the hull is extracted to shorten the model length and to make its boundary layer thickness equivalent to that of a full-scale ship. By using this BLS model, the performance of ESDs on a full-scale can be estimated in a model test. In the present paper, the applicability of the BLS model is investigated by CFD (Computational Fluid Dynamics) simulations of performance estimation of an energy-saving fin in different locations for a bulk carrier. It is found that the BLS model is capable of predicting the full-scale performance of the fins by the model-scale simulations. Moreover, the flow fields affected by the fins with the BLS model are similar to those of full-scale. It is expected that the use of the BLS model enables the prediction of the full-scale performance of ESDs in a model test.