Experimental investigation on roll stability of blunt-nose submarine in buoyantly rising maneuvers

The roll stability of submarine buoyantly rising is investigated by means of kinematics model test in this paper. The physical model design, similarity criteria and experimental procedures are presented in detail for simulating emergency rising of the real submarine with similar properties. Experimental results reveal that the roll and yaw are strongly coupled and interacted. In addition, excessive roll occurs inevitably when underwater drift angle is larger than 5°. In other words, the yaw instability is the most key coupled factor of increasing drift angle as well as generating snap roll, which eventually aggravates the excessive roll. Furthermore, the rising sternplane angle is essential to pitch up nose because a larger pitch rate is conducive to maintain stable heading angle. In summary, by keeping yaw deviation as low as possible helps to limit the increase of drift angle, and further delay the onset of snap roll. Therefore, the excessive roll can be avoided through optimal control of initial speed, blown ballast longitudinal centroid and sternplane angle. The experimental results can provide manipulations recommendations for the emergency rising of the real submarine.