The experimental study on maneuvering derivatives of a submerged body SUBOFF by implementing the Planar Motion Mechanism tests

Abstract

An efficient experimental procedure is established to analyze maneuvering derivatives of a half-scale submerged body DARPA SUBOFF in the horizontal plane for four different types, including bare hull, bare hull with sail, bare hull with rudders, and bare hull with all appendages, by conducting Planar Motion Mechanism (PMM) experiments in the towing tank (176 m × 8 m × 4 m) of National Cheng Kung University (NCKU). The PMM experiments comprise both static test, i.e. oblique towing test, and dynamic tests, i.e. pure sway test, pure surge test, pure yaw test, and yaw test with constant drift angle. In order to obtain high-quality data, a band-pass filter was adopted to pass frequencies within a given range and attenuate high-frequency vibrations as well as background noises. Subsequently, a Fourier transform would be considered to evaluate the maneuvering derivatives based on their motion characteristics. It is worth to mention that the maneuvering derivatives derived from the static tests are in good agreement with the results published by the David Taylor Research Center (DTRC). In the view of steering efficiency, it is inclined to conduct rotation movement rather than transverse movement in SUBOFF operations by analyzing special maneuvering derivatives.