Added Resistance of An Auv Moving Inside A Water Pipeline Due To Wall Proximity

The present paper evaluates the added resistance of a torpedo shaped auv -awing to the wall effect inside a pipe- moving inside a water pipeline. all around the world, there are long extending water or petroleum pipelines which require regular inspection by auvs. in pipes, the auv moves like as a torpedo in launcher. the pipes have limited diameter and because of the wall effects on the fluid flow around the auv, the resistance will be significantly more than the free flow condition. for example the resistance of an auv for d/d equal to 2, is about two times of the free stream. this added resistance should be accounted accurately because it is a necessary requirement for determination of vehicle speed, power demand, range and duration of operation. this paper considers a torpedo shape auv moving inside the pipes with the different diameters. the resistance of this modeling will be compared to the resistance of free steam modeling. this study found that the ratio of d/d equal to 12 could be regarded as critical pipe diameter which added resistance is zero. in restricted diameter pipe the pressure resistance has a main role in total resistance about 45~90 percentages depending on the d/d ratio. this analysis is performed by flow vision (v.2.3) software based on cfd method and solving the rans equations.