ABSTRACT

It is known that DARPA SUBOFF submarine model does not have a horizontal stability in deep water. In this study, the horizontal stability of submarine model moving during the periscope (snorkel) position or close to the free water surface, has been determined in 3 DoF (degrees of freedom). While determining the submarine stability and hydrodynamic maneuvering derivatives, linear coefficients of lateral translational force at different depths and linear coefficients of yaw angular moment were used. The depths were selected as 1.1D, 2.2D, 3.3D and 6D, here D is submarine diameter. The maneuvering derivatives were obtained by performing systematic analyzes with the computational fluid dynamics method. Necessary validation studies were also carried out in computational analyzes. In computational fluid dynamics analysis, longitudinal and lateral force derivatives, and yaw moment derivatives were determined and X0, Xv, Xd, Xẟ, Yv, Yr, Yẟ, Nv, Nr ve Nẟ terms were computed in the linear model. A hydrodynamic model was generated with these coefficients. The horizontal stability was then determined with the effects of different depths by using this hydrodynamic model. It has been found that the submarine model has horizontal stability when cruising close to the free water surface and loses its horizontal stability for water depths greater than 4.6D.