Determination of optimum injection flow rate to achieve maximum micro bubble drag reduction in ships; an experimental approach

Reduction in ship resistance, in order to decrease fuel consumption and also achieve higherspeeds, has been the topic of major research over the last three decades. one of the most attractive ideasin this field is micro bubble drag reduction, which attempts to obtain optimum injection flow rate based onship specifications. the model test results of a 70 cm catamaran model was used to quantify the effect of airinjection rate on drag reduction, and to estimate a simple formulation for calculating an efficient injectionrate by considering the main parameters of the ship, such as: length, width and speed. the test results showthat excessive air injection decreases the drag reduction effect, while suitable injection reduces total dragby about 5%8%.