| Towing tank/water flume experiments are conducted to characterize the dynamics of a Remotely-Piloted Unmanned Underwater Vehicle (RPUUV) propelled by a vectored-thruster system. Force and torque measurements are used to determine the coefficients of drag, lift, yaw-moment and thrust of the vehicle as a function of the vehicle yaw angle and the vectored-thruster rudder angle. Simultaneously, particle Image Velocimetry (PIV) measurements of the propeller inlet flow are also performed to examine the variation of flow conditions at the propeller inlet with rudder angle. The tests are conducted at 0.150 m/s, 0.300 m/s, 0.515 m/s and 0.773 m/s. While the measured drag coefficient is slightly higher than predicted by theory at low Reynolds number (1.44 x10 5 and 2.88 x105), the hydrodynamic coefficients data are expected to be useful in predicting the response of vehicles in the field. Additionally, the magnitude of the thrust vector varies nonlinearly with rudder angle and for nonzero rudder angles the thrust vector does not point in the same direction as the thruster axis. |
