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McCormick, MEBhattacharyya, RMouring, SEDr. Michael E. McCormick:is a research professor of civil engineering at The Johns Hopkins University. Before joining the Hopkins faculty in 1994
he was a professor of ocean engineering for twenty-five years at the U.S. Naval Academy. In addition he has held full-time faculty positions at Swarthmore College Trinity College (Hartford) and the Catholic University of America. He was also a hydrodynamicist at the David Taylor Model Basin for more than four years. Prof. McCormick received his undergraduate degree in mathematics and physics from AmericanUniversity a masters degree in applied mechanics and a Ph.D. in mechanical engineering from Catholic University a Ph.D. in civil engineering and a Sc.D. in engineering science from Trinity College in Dublin Ireland. He has over 100 publications including two books in the areas of ocean engineering wave mechanics and ocean wave energy conversion. He has also edited two books dealing with ocean engineering. In addition he is co-editor of both the journal Ocean Engineering and the Elsevier book series in ocean engineering. Dr. Rameswar Bhattacharyya:is professor of naval architecture at the U.S. Naval Academy
where he has served for twenty-six years and adjunct professor of mechanical engineering at The Johns Hopkins University. Prior to joining the Naval Academy faculty he was a faculty member in the Department of Naval Architecture and Marine Engineering at the University of Michigan. His research experience includes ten years at both the Lubecker Flender-Werke and the Hamburg Ship Model Basin in Germany. His research has led to numerous publications including two books one in the area of ship dynamics and the other in the area of computer-aided ship design. Prof. Bhattacharyya received his undergraduate degree in naval architecture from the Indian Institute of Technology and his doctorate in engineering from the Technical University of Hanover Germany. In addition he holds an honorary doctorate from the University of Veracruz. With Prof. McCormick he co
Panels and all other structural components of surface ships and submarines vibrate when the vessel is underway. The vibratory motions are primarily excited by the power plant. At operational (design) speeds, panels vi...
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Panels and all other structural components of surface ships and submarines vibrate when the vessel is underway. The vibratory motions are primarily excited by the power plant. At operational (design) speeds, panels vibrate in their fundamental modes and those associated with their higher harmonic frequencies. The panel motions have rather well-defined energy spectra, which depend on both the structural design, position of the panel and the rotational speed of the single or multiple power plants. The panel motions will interact with the vortices in the adjacent turbulent boundary layer. The interaction can result in either an increase in the frictional drag or a decrease. Because of this, the argument is made that the designs of the panels and their support systems should include considerations of this hydroelastic effect.
Since its popularization in the late 1970s, Sequential Quadratic Programming (SQP) has arguably become the most successful method for solving nonlinearly constrained optimization problems. As with most optimization me...
Since its popularization in the late 1970s, Sequential Quadratic Programming (SQP) has arguably become the most successful method for solving nonlinearly constrained optimization problems. As with most optimization methods, SQP is not a single algorithm, but rather a conceptual method from which numerous specific algorithms have evolved. Backed by a solid theoretical and computationalfoundation, both commercial and public-domain SQP algorithms have been developed and used to solve a remarkably large set of important practical problems. Recently large-scale versions have been devised and tested with promising results.
An inversion scheme based on normal-mode representation of the acoustic field is applied in ocean acoustic tomography for a range-dependent reconstruction of the sound speed variations at a vertical slice. The scheme ...
An inversion scheme based on normal-mode representation of the acoustic field is applied in ocean acoustic tomography for a range-dependent reconstruction of the sound speed variations at a vertical slice. The scheme is based on the assumption that modal phase can be measured by suitable mode filtering at some range from the sound source. Two cases have been considered. The first of them makes no use of oceanographic information on the variability to be recovered, while the second one makes use of empirical orthogonal functions (EOFs) that describe sound speed variations in the ocean. The data used in the applications presented in this paper are synthetic ones. It is shown that both modal inversion schemes can be used for the recovery of range-dependent sound speed variations of compact support in the ocean, provided that a range dependent background environment is used to describe an initial guess of the variations. The scheme is more powerful when EOFs are used.
In this paper we present an algorithm for the density and sound speed reconstruction of a two-layered bottom consisting of a fluid sediment layer over a fluid substrate of semi-infinite extend. The thickness of the se...
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In this paper we present an algorithm for the density and sound speed reconstruction of a two-layered bottom consisting of a fluid sediment layer over a fluid substrate of semi-infinite extend. The thickness of the sediment as well as the attenuation coefficients in the botton layer are also recovered. Measurements of the reflection coefficients of plane waves for eight source frequencies incident normally upon the water bottom interface are needed. The minimum number of frequencies needed for the algorithm is eight as it will be seen in the following sections, however if the reflection coefficient is known for more than eight frequencies the method makes use of the excess frequencies, improving the final solution in a postprocessing way. We first introduce our model, explain the method of solution and present the major steps of the algorithm. Then we will show results using synthetic data, for four cases which were tested, as well as results from a tank experiment.< >
A model for case II diffusion into polymers is presented. The addition of stress terms to the Fickian flux is used to produce the characteristics progressive front. The stress in turn obeys a concentration-dependent e...
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A model for case II diffusion into polymers is presented. The addition of stress terms to the Fickian flux is used to produce the characteristics progressive front. The stress in turn obeys a concentration-dependent evolution equation. The model equations are analyzed in the limit of small diffusivity for the problem of penetration into a semiinfinite medium. Provided that the coefficient functions obey two monotonicity conditions, the solvent concentration profile is shown to have a steep front that progresses into the medium. The formulas governing the progression of the front are developed. After the front decays away, the long time behavior of the solution is shown to be a similarity solution as in Fickian diffusion. Two techniques for approximating the solvent concentration and the front position are presented. The first approximation method is a series expansion; formulas are given for the initial speed and deceleration of the front. The second approximation method uses a portion of the long time similarity solution to represent the short time solution behind the front.
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