Simulation and experimental research on hydrodynamic performance of fully attached submarine in the surface and near the surface modes

Abstract

The switch between the surface and near-surface modes is critical to the hydrodynamic performance of the submarines. In this study, based on tank experiments, an improved delayed detached-eddy simulation (IDDES) method based on the shear stress transport (SST) K-Omega was tested for its ability to predict the hydrodynamic coefficients of submarines with satisfactory results. By expanding the simulation range, the changes in the hydrodynamic performance of the submarine on and near the water surface were analyzed with respect to force coefficient, flow field, maximum wave height, and maximum ray angle. The change in the drag coefficient of the hull has a water surface mode and near-water surface mode, which leads to a peak value of the drag coefficient at different submerged depths. When a "hump" phenomenon occurs at high Froude number(Fr = 0.5), the flow separation at the stern shoulder of the hull weakens, resulting in an increase in wake velocity and ray angle. The numerical simulation results showed that the Rabaud and Moisy model has better applicability, but when Fr > 0.8 and Hd > 1.5, the theory underestimates the maximum ray angle.