Numerical Analysis of the Drag Reduction Performance of a Double M-Ship Boat With Stepped Planning-Air Coupling

Abstract

Abstract In this paper, analyze the influence of the stepped planning structure on the drag performance by observing waveform diagrams at the stern of the double M-ship and water–air and pressure distribution diagrams at the bottom of the ship. This study uses the combined stepped planning-air drag reduction technology to improve the sailing characteristics of the double M-ship. Research findings: The stepped planning contributes to a reduction in bottom pressure, enhances water–air distribution, and augments the amplitude of hull movement. Within the design speed range, the maximum drag reduction rate achieved by the stepped planning is 7.574%. However, this enhancement comes at the expense of increased viscous pressure resistance, which becomes the predominant resistance when sailing at full speed; Injecting air at the stepped planning can effectively reduce the viscous pressure resistance increased by the stepped planning. The combined drag reduction technology of stepped planning and air successfully realizes the total drag reduction at the double-M ship's high speed. The total resistance experienced when air is injected at the stepped planning is reduced by up to 20.981% compared to the original hull.