Numerical investigation on the drag characteristics of AUV hulls

Abstract

Autonomous Underwater Vehicles (AUVs) are self-propelled robotic platforms that carry a suite of instruments and sensors which enable the vehicle to navigate the depths of the ocean using its onboard power. Due to the limited power onboard the vehicle, efficient streamlining is an important design consideration for maximum endurance of a cruising type AUV. Torpedo-shaped hull forms are very common among cruising type AUVs, which consist of a nose section, a cylindrical mid-body section, and a tail section. This paper discusses different torpedo-shaped bare-hulls formed by changing the nose and tail sections to identify which combination of nose and tail renders the most hydrodynamically efficient hull form. A torpedo-shaped AUV bare-hull for which experimental results were available is selected as the base model and CFD analysis is performed and validated. With the validated CFD model, the different shaped hull configuration is changed by modifying its nose and tail profiles. A total of seven configurations were analyzed for three different speeds. The least drag shaped configuration is identified and recommended for further inclusion of control surfaces.