Date of Award

2022

Degree Type

Capstone Project

First Advisor

Dr. Bahram Nassersharif

Abstract

Team 02 in part with Dr. Nassersharif, has been commissioned by the Naval Undersea Warfare Center to provide an optimal design and modeling for towed undersea vehicles. The proposed effort served to study, evaluate, and model the drag for the towing of cylindrical undersea vehicles. This project will model towing configurations for both single and multiple vehicle configurations. Recommendations were also made regarding the propulsion configuration of the leading vehicle. The proposed design solution aimed to achieve a drag coefficient of less than 0.3 to minimize the effect the towed vehicle may have on the range and endurance of its host. Range and endurance remain among the biggest factors that inhibit mission capability. For this reason, R.E.M.OR.A. was designed to induce well under a 500 Watt power loss from the drag of the vehicle(s). The effort included extensive initial research into methods that would aid in this study. Multiple C.F.D. simulations were run to obtain theoretical results for coefficients of drag on proposed shape estimations as well as the effects on varied surface roughness. As the Naval application has specified implications, one being undetected operation, measures were taken to minimize the acoustic power output of the proposed propulsion configurations. C.F.D.’s were also run on these configurations, that for a single screw propulsor and a 4 screw propulsor system. The efforts sought to reduce the noise output of the propulsion system to be less than 30 decibels. These targets were confirmed by in water testing of the proposed shape estimation where drag forces were obtained and respective coefficients calculated. From this testing quadratic models were created to predict power loss induced by full scaled model of the system. The proposed solution was found to have an almost negligible effect on full sized host vehicles, especially those that are nuclear powered. The loss of power for a single and dual vehicle both remained under 115 Watts after scaling test values obtained from in water testing. The experimental drag coefficients of these setups remained just under 0.3 with an average value of 0.286. These vehicles were optimized with a dynamic attachment point capable of varying the angle and point of attachment to the vehicle. This system allowed the operational target depth of 200-300ft.

Comments

Team Name: Team 2, The REMORA Program

Sponsor: Naval Undersea Warfare Center (NUWC)

Sponsor Representative: Ret. Col. Michael T. Ansay

Document Reference: URI-MCE-402-002-2022

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