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

This paper investigates the variation in the uniformity of the wake field on the propeller disk of an underwater vehicle according to the tail fin axial position and angle of run of the stern, and reveals the influence mechanism of the stern structure on the wake field.

Numerical simulation analysis of the underwater vehicle is carried out using the computational fluid dynamics (CFD) method, and Gaussian process modeling analysis is performed for the wake field inhomogeneity index to explore the response relationship between structure-field performance within the design range, analyze the sensitivity of the stern structure to wake field inhomogeneity, and search for a Suboff stern structure with excellent wake field homogeneity.

As the results show, with a fixed tail fin axial upwind area to ensure the operation performance and sailing efficiency of the underwater vehicle, the tail fin axial position and angle of run of the stern have a large impact on the propeller disk inhomogeneity; when the angle of run of the stern is $\theta ={10}^{\circ }$, the backward movement of the tail fin axial reduces the propeller disk inhomogeneity, and the wake objective function (WOF) decreases from 0.124 5 to 0.091 4; when the angle of run of the stern is $\theta ={20}^{\circ }$, the backward movement of the tail fin axial causes the inhomogeneity of the propeller disk to first increase and then decrease, and the WOF increases from 0.1049 to 0.1145, then decreases to 0.1068; when the tail fin axial position is $h=$3.810 0 m, the increase of the angle of run of the stern makes the propeller disk inhomogeneity decrease, and the WOF decreases from 0.124 5 to 0.104 9; and when the tail fin axial position is $h=$4.114 8 m, the increase of the angle of run of the stern makes the propeller disk inhomogeneity increase, and the WOF increases from 0.091 4 to 0.106 8. This shows that 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.

For a Suboff model with a fixed stern upwind area, a configuration with a large tail fin axial position and small angle of run of the stern can significantly enhance the propeller disk wake field uniformity. The findings of this study can provide useful references for the design of the stern structures of underwater vehicles.