• International Journal of Naval Architecture and Ocean Engineering
• /
• 제12권1호
• /
• pp.843-855
• /
• 2020

X-plane submarines show better maneuverability as they have much longer span of control plane than that of cross plane submarines. In this study, captive model tests were conducted to evaluate the maneuverability of an X-plane submarine using Computational Fluid Dynamics (CFD) and a mathematical maneuvering model. For CFD analysis, SNUFOAM, CFD software specialized in naval hydrodynamics based on the open-source toolkit, OpenFOAM, was applied. A generic submarine Joubert BB2 was selected as a test model, which was modified by Maritime Research Institute Netherlands (MARIN). Captive model tests including propeller open water, resistance, self-propulsion, static drift, horizontal planar motion mechanism and vertical planar motion mechanism tests were carried out to obtain maneuvering coefficients of the submarine. Maneuvering simulations for turning circle tests were performed using the maneuvering coefficients obtained from the captive model tests. The simulated trajectory showed good agreement with that of free running model tests. From the results, it was proved that CFD simulations can be applicable to obtain reliable maneuvering coefficients for X-plane submarines.

• 대한조선학회논문집
• /
• 제59권5호
• /
• pp.306-313
• /
• 2022

Most submarines use the cross-plane, which is convenient and inexpensive, but the number of submarines equipped with an X-plane is increasing recently. This study focuses on designing the control system of the X-plane submarine with various control methods and analyzing the effect of each controller. First, a maneuvering simulation environment for a subjected submarine is established. The dynamics and the operating range of control surfaces are considered. Second, a depth and heading control system of the submarine, which can be divided into three parts, is designed: guidance, controller, and control allocation. The guidance system generates a smooth desired depth and heading. The controller is designed using Proportional-Integral-Differential (PID), Linear Quadratic Regulator (LQR), and H-infinity (H∞) control methods. A linear control allocation method is used to distribute control moment calculated by the controller to the control surfaces. Finally, the designed control system is applied to a subjected X-plane submarine, and a depth and heading control simulations are performed. Each control method is compared and analyzed under various simulation conditions.

• 대한조선학회논문집
• /
• 제59권5호
• /
• pp.288-295
• /
• 2022

In this study, the force and moment acting on a Joubert BB2 submarine model at depths near the free surface were measured through a captive model test with the scale ratio of 1/15. Based on the experiment, the pitch moment and heave force due to the "Tail suction effect", including the change in surge force with depth near the free surface, were quantitatively analyzed. The change of force and moment according to the relative position of the sail and the free surface was reviewed with the free surface waves generated for each depths. As a result, the angle of attack of the hull to counteract the pitch moment induced by the tail suction effect was derived. The effect of the hydrostatic moment component according to the angle of attack on the equilibrium of pitch moment was also taken into account. The control plane performance tests for the X-type rudder and sail plane were conducted in snorkel and surface depth conditions to figure out the control plane angles for the neutral level flight of the submarine at near free surface. The results of this study are expected to be used as a reference data for the neutral level flight of the submarine at near free surface operation in the free running model test as well as numerical studies.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제13권1호
• /
• pp.351-351
• /
• 2021

• 대한조선학회논문집
• /
• 제59권6호
• /
• pp.423-431
• /
• 2022

In this paper, the results of Planar Motion Mechanism (PMM) test for a 1/15 scaled model of the MARIN Joubert BB2 submarine is dealt with to derive the maneuvering coefficients for surface condition. For the depth of surface navigation, the top of the sail was exposed 0.46 m above the water surface in the model scale, and it corresponds to 6.9 m in the full scale. The resistance and self-propulsion tests were conducted, and the model's self-propulsion point was obtained for 1.328 m/s, which corresponded to 10 knots in the full scale. The maneuvering tests were performed at the model's self-propulsion point, and the maneuvering coefficients were obtained. Based on the maneuvering coefficients, a turning simulation was performed for starboard 30 degree of stern fins. The straight-line stability and control effectiveness in the horizontal plane were analyzed using the maneuvering coefficients and compared with the appropriate range. For the analysis of the neutral fin angle of the X-type stern fin, the stern fin test with drift angles was carried out. As a result, the flow straightening effect at lower and upper parts of the stern fin was discussed.