Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, March 2005. / Thesis Advisor(s): Fotis Papoulias. Includes bibliographical references (p. 63-64). Also available online.

Thesis (M.Eng.)--Memorial University of Newfoundland, 2003. / The CD-ROM contains Appendix D: mass spectrometer data. Bibliography: leaves 94-97.

Thesis (M.S.)--Rochester Institute of Technology, 2006. / Typescript. Includes bibliographical references (leaves 132-137).

Thesis (Master of Engineering in Mechanical Engineering)--Cape Peninsula University of Technology, 2018. / Underwater glider wings are the lifting surfaces of unmanned underwater vehicles UUVs depending on the chosen aerofoil sections. The efficiency as well as the performance of an underwater glider mostly depends on the hydrodynamic characteristics such as lift, drag, lift to drag ratio, etc of the wings. Among other factors, the geometric properties of the glider wing are also crucial to underwater glider performance. This study presents an opportunity for the numerical investigation to improve the hydrodynamic performance by incorporating curvature at the trailing edge of a wing as oppose to the standard straight or sharp trailing edge. A CAD model with straight leading edge and trailing edge was prepared with NACA 0016 using SolidWorks 2017. The operating conditions were setup such that the inlet speed varies from 0.1 to 0.5 m/s representing a Reynolds number 27.8 x 10ᵌ and 53 x 10ᵌ. The static pressure at different angles of attack (AOA) which varies from 2 to 16degrees at the increment of 2degrees for three turbulent models (K-Ԑ-standard, K-Ԑ-RNG and K-Ԑ-Realizable), was computed for upper and lower surfaces of the modified wing model using ANSYS Fluent 18.1. Thereafter the static pressure distribution, lift coefficient, drag coefficient, lift to drag ratio and pressure coefficient for both upper and lower surfaces were analysed. The findings showed that the lift and drag coefficient are influenced by the AOA and the inlet speed. If these parameters change the performance of the underwater glider changes as depicted by figure 5.6 and figure 5.7. The hydrodynamics of the underwater glider wing is optimized using the Cʟ/Cᴅ ratio as function of the operating conditions (AOA and the inlet speed). The investigation showed that the optimal design point of the AOA of 12 degrees and a corresponding inlet speed of 0.26m/s. The critical AOA matched with the optimal design point AOA of 12 degrees. It was also observed that Cp varies across the wing span. The results showed the Cp is higher closer to the fuselage while decreasing towards the mid-span and at the tip of the wing. This showed that the wing experiences more stress close to the fuselage than the rest of the wing span which implies that a higher structural rigidity is required close to the fuselage. The results of the drag and lift curves correspond to the wing characteristics typical observed for this type of aerofoil.

Thesis (S.M.)--Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Ocean Engineering; and the Woods Hole Oceanographic Institution), 1996. / Includes bibliographical references (leaves 69-71). / by Erik Alfred Burian. / S.M.

Thesis (MScEng (Electrical and Electronic Engineering))--Stellenbosch University, 2008. / A navigation performance sensitivity study with respect to the quality variation of sensors and sensor combinations is presented in this thesis. Navigation simulation software capable of using real-time and simulated sensor data is developed in this project. The simulation software is used to simulate different sensor combinations and therefore evaluate the best configuration for each AUV mission. A sensor module is also developed to capture real-time sensor data. The sensor module includes a low-cost 6-degreeof- freedom inertial measurement module (rate gyroscopes and accelerometers), a three-axes magnetometer and other sensor interfaces. The real-time sensor data are used to test and calibrate the navigation simulation software. Different sensor combinations are evaluated by using the navigation simulation software with simulated sensor data as input. The quality of each sensor is varied by changing its noise characteristics. The performance study, together with the developed simulation tools, simplifies the process of selecting a sensor combination to fulfill a specific navigation accuracy requirement.

Approved for public release; distribution is unlimited / This thesis centers around actual field operations and post-mission analysis of data acquired using a REMUS AUV operated by the Naval Postgraduate School Center for Autonomous Underwater Vehicle Research. It was one of many platforms that were utilized for data collection during AOSN II, (Autonomous Oceanographic Sampling Network II), an ONR sponsored exercise for dynamic oceanographic data taking and model based analysis using adaptive sampling. The vehicle's ability to collect oceanographic data consisting of conductivity, temperature, and salinity during this experiment is assessed and problem areas investigated. Of particular interest are the temperature and salinity profiles measured fromlong transect runs of 18 Km. length into the southern parts of Monterey Bay. Experimentation with the REMUS as a mine detection asset was also performed. The design and development of the mine hunting experiment is discussed as well as its results and their analysis. Of particular interest in this portion of the work is the issue relating to repeatability and precision of contact localization, obtained from vehicle position and sidescan sonar measurements. / Lieutenant, United States Navy

This dissertation concerns the dynamics and control of an autonomous underwater vehicle (AUV) which uses internal actuators to stabilize its horizontalplane motion. The demand for high-performance AUVs are growing in the field of ocean engineering due to increasing activities in ocean exploration and research. New generations of AUVs are expected to operate in harsh and complex ocean environments. We propose a hybrid design of an underwater vehicle which uses internal actuators instead of control surfaces to steer. When operating at low speeds or in relatively strong ocean currents, the performances of control surfaces will degrade. Internal actuators work independent of the relative ows, thus improving the maneuvering performance of the vehicle. We develop the mathematical model which describes the motion of an underwater vehicle in ocean currents from first principles. The equations of motion of a body-fluid dynamical system in an ideal fluid are derived using both Newton-Euler and Lagrangian formulations. The viscous effects of a real fluid are considered separately. We use a REMUS 100 AUV as the research model, and conduct CFD simulations to compute the viscous hydrodynamic coe cients with ANSYS Fluent. The simulation results show that the horizontal-plane motion of the vehicle is inherently unstable. The yaw moment exerted by the relative flow is destabilizing. The open-loop stabilities of the horizontal-plane motion of the vehicle in both ideal and real fluid are analyzed. In particular, the effects of a roll torque and a moving mass on the horizontal-plane motion are studied. The results illustrate that both the position and number of equilibrium points of the dynamical system are prone to the magnitude of the roll torque and the lateral position of the moving mass. We propose the design of using an internal moving mass to stabilize the horizontal-plane motion of the REMUS 100 AUV. A linear quadratic regulator (LQR) is designed to take advantage of both the linear momentum and lateral position of the internal moving mass to stabilize the heading angle of the vehicle. Alternatively, we introduce a tunnel thruster to the design, and use backstepping and Lyapunov redesign techniques to derive a nonlinear feedback control law to achieve autopilot. The coupling e ects between the closed-loop horizontal-plane and vertical-plane motions are also analyzed. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Autonomous Underwater Vehicle (AUV) depth control methods typically use a pressure sensor to measure the depth, which results in the AUV following the trajectory of the surface waves. Through simulations, a controller is designed for the Ocean Explorer AUV with the objective of the AUV holding a constant depth below the still water line while operating in waves. This objective is accomplished by modeling sensors and using filtering techniques to provide the AUV with the depth below the still water line. A wave prediction model is simulated to provide the controller with knowledge of the wave disturbance before it is encountered. The controller allows for depth keeping below the still water line with a standard deviation of 0.04 and 0.65 meters for wave amplitudes of 0.1-0.25 and 0.5-2 meters respectively and wave frequencies of 0.35-1.0 𝑟𝑎𝑑⁄𝑠𝑒𝑐, and the wave prediction improves the depth control on the order of 0.03 meters. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

Underwater vehicles often use acoustics or dead reckoning for global positioning, which is impractical for low cost, high proximity applications. An optical based positional feedback system for a wave tank operated biomimetic station-keeping vehicle was made using an extended Kalman filter and a model of a nearby light source. After physical light model verification, the filter estimated surge, sway, and heading with 6 irradiance sensors and a low cost inertial measurement unit (~$15). Physical testing with video feedback suggests an average error of ~2cm in surge and sway, and ~3deg in yaw, over a 1200 cm2 operational area. This is 2-3 times better, and more consistent, than adaptations of prior art tested alongside the extended Kalman filter feedback system. The physical performance of the biomimetic platform was also tested. It has a repeatable forward velocity response with a max of 0.3 m/s and fair stability in surface testing conditions. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection