Hydrodynamic coefficients of the DARPA SUBOFF AFF-8 in rotating arm maneuver - Part Ⅱ: Test results and discussion

Abstract

The study of submarine maneuverability is an important part in the overall design of submarines. The goal of this investigation is to study the hydrodynamic coefficients of SUBOFF AFF-8 in rotating arm maneuver. This paper consists of two parts, which deal with the test technology and test results, respectively. Part Ⅱ of this paper presents the angular velocity-dependent derivatives and spatial coupling coefficients of SUBOFF AFF-8 and investigates the forces and moments in steady turn. The forces and moments of SUBOFF AFF-8 are investigated and the hydrodynamic coefficients of SUBOFF AFF-8 are fitted. The results show the coefficients with r in the lower corner represent the linearity of hydrodynamic forces. In order to get more accurate nonlinear coefficients and coupling coefficients, the drift angle should not be too small in the rotating arm test. When SUBOFF AFF-8 has both drift angle and attack angle, the nonlinear degree of rotation increases sharply, which will bring great difficulties to the measurement of forces and moments.