Influence of SUBOFF stern structure on the wake field quality at the propeller disk with fixed stern upwind area

Objectives To investigate the variation of the uniformity of the wake field on the propeller disk of an underwater vehicle with the rudder position and the inflow angle, and reveal the influence mechanism of the stern structure on the wake field. Methods Numerical simulation analysis of underwater vehicle is carried out by computational fluid dynamics method, and Gaussian process modeling analysis is performed for the index of wake field inhomogeneity to explore the response relationship between structure-field performance within the design range, to analyze the sensitivity of the stern structure to the wake field inhomogeneity, and to search for SUBOFF stern structure with excellent wake field homogeneity. Results The results show that, with constant rudder upwind area to ensure the efficiency of underwater vehicle operation performance and sailing, the rudder position and inflow angle have a large impact on the propeller disk inhomogeneity; when the inflow angle is 10°, the backward movement of the rudder reduces the propeller disk inhomogeneity, and the wake objective function (WOF) decreases from 0.1245 to 0.0914; when the inflow angle is 20°, the backward movement of the rudder causes the inhomogeneity of the propeller disk to first increase and then decrease, and the WOF increases from 0.1049 to 0.1145 and then decreases to 0.1068; when the rudder position is 3.8100 meters, the increase of the inflow angle makes the propeller disk inhomogeneity decrease, and the WOF decreases from 0.1245 to 0.1049; when the rudder position is 4.1148 meters, the increase of the inflow angle makes the propeller disk inhomogeneity increase, and the WOF increases from 0.0914 to 0.1068; the adjustment of the SUBOFF stern structure using Gaussian process modeling analysis can effectively reduce the inhomogeneity of the wake field on the propeller disk; moreover, the global sensitivity of the stern geometry to the quality of the wake field are close, while there are significant differences in local sensitivity. Conclusions The study shows that for the SUBOOF model with fixed stern upwind area, the large rudder position and small inflow angle configuration can significantly enhance the propeller disk wake field uniformity, which provides guidance for the design of the stern structure of underwater vehicles.