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

In this paper, analyze the influence of the stepped planing 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 the combined stepped planing-air drag reduction technology to improve the sailing characteristics of the double M-ship. Research findings: The stepped planing 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 planing 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 planing can effectively reduce the viscous pressure resistance increased by the stepped planing. The combined drag reduction technology of stepped planing 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 planing is reduced by up to 20.981% compared to the original hull.