The Unmanned Undersea Vehicle(UUV) which had taken the shape of manta was proposed by Lee et al.. It was called Manta-type Unmanned Undersea Test Vehicle(MUUTV) by Bae et al.. MUUTV is based on the same design concept as UUV called Manta Test Vehicle, which was originally built and operated by the Naval Undersea Warfare Center.
In order to evaluate motion stability of originally proposed MUUTV, linear equations of motion were adopted and a calculation method for estimating hydrodynamic derivatives was proposed. Based on the proposed calculation method, discussions were made to examine improvement in motion stability through gradual changes in appendage design of MUUTV. As a result, the directional stability in vertical plane was improved by increasing the area of stern horizontal planes, and the straight-line stability in horizontal plane was also improved by removal of lower vertical plate and by adjusting the area and the position of upper vertical plate simultaneously.
Numerical simulation was carried out to evaluate manoeuvring motion characteristics of MUUTV of which motion stability had been improved. Mathematical model for numerical simulation of manoeuvring motion with 6 degrees of freedom is derived from captive model experiment in circulating water channel and some parts are referred to NSRDC standard submarine motion by Feldman. Some of the hydrodynamic derivatives are obtained from model experiment but the rest of them are estimated from the prediction method suggested. According to the present simulation result, it is ascertained that the proposed MUUTV has taken the proper manoeuvring motion characteristics. In order to calculate the sensitivity indices of hydrodynamic derivatives on MUUTV, the method by Sen was adopted. Through this analysis, significance of hydrodynamic derivatives are found out, and also the numerical simulation using simplified mathematical model based on result of sensitivity analysis is ascertained to be enough for prediction of manoeuvring characteristics of MUUTV.
Finally, numerical simulation of extreme motion due to operation of hovering thrusters is carried out. Previous mathematical model is basically adopted, but some parts are modified according to captive model experiment with large angle of attack and hovering thruster experiment.