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The effect of fin and jet vortex generators on the crossflow separation of a 688 class submarine in a turning maneuver was studied. The vortex generators are located on the top and bottom centerline of the submarine. The intent of the vortex generators is to improve turning performance by changing the hydrodynamic forces incurred from crossflow separation. Performance of the jets and the fins are compared. Oil flow visualization and force and moment measurements were used as the primary diagnostics in determining the effectiveness of various vortex generator configurations. The fins were found to be very effective in delaying cross flow separation, while the jets were less effective. In addition, the oil flows revealed the importance of locating vortex generators near the bow and the critical role the sail plays in the fluid dynamics near the submarine. Overall, the fins were found to be viable as a concept for flow control, while the jets were less attractive. / Master of Science

The loss of the nuclear-powered submarine USS Thresher (SSN 593) acted as a catalyst that accelerated improvements in submarine design, construction and operations. Such improvements resulted in a substantially safer submarine force, thereby making it more operationally reliable. The disaster also dramatically increased the influence of Admiral Hyman G. Rickover in submarine development by giving him the opportunity to promote the system of management he used as head of the U.S. Navy's Nuclear Propulsion Branch. During Congressional hearings on the loss of the Thresher, Rickover convinced members of the Joint Committee on Atomic Energy that his management system, based upon stringent standards of quality control and principles of engineering, was the standard that should be applied to submarine development. The disaster also highlighted the need for greatly improved deep-submergence capabilities within the fleet. Subsequently, deep-ocean search, location and recovery assets were developed, as well as improved deep-sea rescue capabilities. / M.A.

An investigation of the flow field during eject of a cruise missile from the launch tube was undertaken using a "cold" flow simulation. A facility was developed whereby various design changes in the missile ejection apparatus, denoted the vertical support assembly, could be quickly and easily assessed in terms of the relative effects on the flow field. Flow visualization techniques using fluorescent dye allowed for documentation of flow patterns in the baseline configuration, such as backflow, jetting, and recirculation regions, as well as for the location of several potential hot spots. The mixing of the fuel-rich gas generator effulent and the air in the launch tube was assessed by thermocouple measurements; warm water was used to simulate the exhaust while ambient water represented the air initially contained in the launch tube. The results have shown that air is inefficiently mixed in large portions of the vertical support assembly volume. However, strong flameholding zones are established in the region vacated by the accelerating missile, where it is believed that secondary combustion could occur. The flow field characterization has shown that considerable improvements to system performance should be possible through geometrical changes to promote more efficient mixing. / M.S.

CIVINS / The United States Navy has recognized the rising age of its nuclear reactors. With this increasing age comes increasing importance of backup generators. In addition to the need for decay heat removal common to all (naval and commercial) nuclear reactors, naval vessels with nuclear reactors also require a backup means of propulsion. All underway Navy nuclear reactors are operated with diesel generators as a backup power system, able to provide emergency electric power for reactor decay heat removal as well as enough electric power to supply an emergency propulsion mechanism. While all commercial nuclear reactors are required to incorporate muhiple backup generators, naval submarine nuclear plants feature a single backup generator. The increasing age of naval nuclear reactors, coupled with the dual reqmrements of a submarine's solitary backup generator, makes the study of submarine backup generators vital. / CIVINS / US Navy (USN) author

O projeto de submarinos é um tema que vem se desenvolvendo há muitos anos. No Brasil, vivemos um momento de pleno avanço na área, sendo encabeçado pela Marinha do Brasil com o desenvolvimento do primeiro submarino de propulsão nuclear brasileiro. No decorrer desse projeto, diversos estudos devem ser desenvolvidos, dentre eles, ensaios com modelos em escala, que serão realizados em um túnel de cavitação. Durante estes experimentos, espera-se que surjam diversas fontes de incerteza, que podem comprometer os resultados obtidos, destacando-se o efeito de blocagem hidrodinâmica. Nesse contexto, esta dissertação apresenta uma investigação do fenômeno de blocagem no modelo de submarino DARPA SUBOFF na seção de testes de um túnel de cavitação. Para isso, simulações tridimensionais de média de Reynolds (RANS) foram realizadas para o modelo de submarino posicionado no túnel (sob blocagem) e sob condição de águas profundas (referência), para diferentes ângulos de ataque e número de Reynolds (Re) constante. Coeficientes de força e momento hidrodinâmicos foram obtidos e os métodos de correção de blocagem clássico e WICS foram empregados para obter fatores que pudessem corrigir esses valores. A eficiência de cada método foi avaliada comparando os valores corrigidos com os de referência. Os resultados mostraram que ambos métodos de correção são eficientes na recuperação de coeficientes de força e momento hidrodinâmicos para razões de blocagem inferiores a 10%, mas ressalvas são feitas quanto à utilização de cada um desses métodos, sendo o método clássico indicado para o estudo de geometrias simples e o método WICS para modelos mais complexos. Paralelamente, a topologia do escoamento ao redor do submarino foi estudada através do método dos pontos críticos, para avaliar se a blocagem hidrodinâmica pode causar alterações nas estruturas presentes no escoamento. A análise topológica permitiu avaliar a evolução nas estruturas do escoamento para os ângulos de ataque e Re simulados. Foram capturadas as linhas de separação no corpo e avaliada sua relação com a tensão de cisalhamento ao longo do casco. A blocagem hidrodinâmica não causou alterações drásticas na topologia do escoamento. / The Project of submarines has been in development for years. In Brazil, we are facing a moment of full progress in this area, leaded by the Brazilian Navy with the development of the first submarine with nuclear propulsion in the country. During this project, many studies will be developed, among them, experiments with scaled models, that will be performed in a cavitation tunnel. Throughout these experiments, many sources of uncertainty are expected to arise that may compromise the results obtained, one effect that stands out is the hydrodinamic blockage. In this context, this master\'s thesis presents an investigation of the blockage phenomenon in the submarine model DARPA SUBOFF placed in the test section of a cavitation tunnel. To accomplish this, tridimensional simulations of Reynolds-Averaged Navier Stokes equations (RANS) were performed to the submarine model placed in the tunnel (under blockage) and in deep water condition (reference), to a variety of angles of attack and a constant Reynolds Number (Re). Cofficients of hydrodynamic forces and moment were measured and the classic and WICS correction methods were used to obtain factors that could correct these values. The efficiency of these methods were evaluated comparing the corrected values with the reference ones.The results showed that both correction methods are efficients in the recovery of hydrodynamic forces and moment to blockage ratios below 10%, but reservations are made about the use of each method. The classic method is suggested when simple geometries are tested and the WICS method when more complex models are used. At the same time, the flow topology around the submarine was studied, using the critical point theory, to evaluate if the hydrodynamic blockage can cause changes in the structures in the flow. The topology analysis permited to assess the evolution of structures in the flow to the conditions of angle of attack and Re simulated. Separation lines were captured in the body and their relationship with the shear stress in the hull was evaluated. The hydrodynamic blockage did not cause drastic changes in the flow topology.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaf 72. / by Calvin McCoy Winey III. / M.S.

Thesis (M.S.)--Mississippi State University. Department of Aerospace Engineering. / Title from title screen. Includes bibliographical references.

Thesis (M.S.)--Naval Postgraduate School, 2003. / "June, 2003." Includes abstract. DTIC report no.: ADA417061. Includes bibliographical references (p. 87-90). Full text available online from DTIC.

Thesis (Degrees of Naval Engineer and M.S. in Mechanical Engineering)--Massachusetts Institute of Technology, 2006. / "June 2006." Description based on title screen as viewed on June 1, 2010. DTIC Descriptor(s): Maintenance, Diesel Engines, Nuclear Reactors, Generators, Nuclear Powered Submarines, Commerce, Emergencies, Submarines, Standby Generators, Backup Systems, Auxiliary Power Plants, Naval Vessels, Navy, Propulsion Systems, Electric Power, Supplies. Includes bibliographical references (p. 41). Also available in print.