Verification of simulation for unwinding motion of cable in water by physical experiment

When a torpedo is launched from a mother ship, a fiber-optic cable that exchanges information between the torpedo and the mother ship is unwound from a spool so as to enhance the shoot-down performance. The unwinding motion of the fiber-optic cable has been numerically analyzed using steady- or transient-state equations of motion, but the simulation has not been verified by physical experiments. Therefore, in this study, the numerical results for the unwinding cable are verified with a lab-based physical experiment. The experiment considers realistic situations in which the cable is unwound from an outer spool package with three different unwinding velocities in water. The transient-state equation of motion is derived in a Cartesian coordinates system using Hamilton's principle for an open system. In conclusion, the numerical results are similar to the motion of the unwinding cable in the physical experiment. Particularly, the numerical results indicate that the motion observed in the physical experiment coincides better with the simulation as the unwinding velocity decreases.