Experimental Determination of an AUV's Drag Resistance in a Towing Tank

Abstract

The market for AUVs has expanded dramatically over the past several decades, a trend that is expected to continue over the next 10 years. AUVs operate autonomously using a dynamic controller that accounts for the dynamics of the system, including the drag resistance of the AUV. This paper examines the method of using a calm-water resistance test in a towing tank to determine the resistance of an AUV. A scale model of a survey class AUV was created using a 3d printer and mounted in a towing tank. The model was towed, and the resistance force recorded for a range from 0.3 to 0.9 m/s. An estimation of the AUV’s resistance was determined using this data. The average drag coefficient was calculated at each speed using this data. The average drag coefficient was fit to a linear curve with the logarithm of the Reynolds number of the form Cd = a∗log₁₀(Re) + b where a = −0.0771 ± 0.0507 and b = 0.484 ± 0.277.