Experimental investigation on ship’s model in carrying out energy economics of BDR/ALS methodology

For vessels moving at slower speeds, the frictional resistance contributes up to 80% of the total resistance, demanding a reduction in it. In the BDR/ALS technique, to reduce frictional resistance, the air is injected below the moving body, which is one of the active and interesting research topics. In this work, to reduce the total resistance and the energy required to run a ship, experimental investigations were performed on a 1:23 scaled model of 8000 Tonnes Deadweight Bulk Carrier for a Froude number range of 0.06 to 0.18. For each speed of operation, consequences of different air injection rates of 0.5 to 3.0 CFM, and different sizes of injection holes were thoroughly investigated. With the injection holes of 2mm and 1mm in diameter, the maximum savings in the energy of 29.2% and 25.1% were observed at the Froude numbers of 0.09 and 0.11, respectively.