An autonomous underwater vehicle (AUV) "Rainbow" has been developed in Kyushu University. The vehicle is an ocean observation robot to measure space continuous data to complement ocean acoustic tomography or remote sensing by an artificial satellite. The AUV is system independent of the outside, so that it has to save energy stored in the vehicle during a cruise; for this purpose, a shape with low resistance is desirable. Efficiency of the propeller depends on the flow field around the vehicle, so that a design taking into consideration mutual interference between the propeller and the body is needed for optimal cruising range. In this study, calculations of the flow field around the body were carried out based on computational fluid dynamics and the body shape was optimized to reduce the resistance and to improve efficiency of the propeller. The drag coefficient of the body based on the calculated flow field is compared to experimental results. Effect of the body shape on drag and efficiency of the propeller are investigated and optimization of the body shape is discussed.
Observation of the ocean is essential to solve problems plaguing the global environment. In recent years, several new methods for ocean observation have been developed such as ocean acoustic tomography and remote sensing by an artificial satellite. These methods are very efficient and enable the gathering of data over a wide sea area within a short period. However, they are indirect measurements and directly measured data is required for calibration or complementation of the information. An autonomous underwater robot for ocean observations has been developed in Research Institute for Applied Mechanics of Kyushu University to measure data to be used in calibrating and complementing that gathered by ocean acoustic tomography or remote sensing by an artificial satellite.