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OPENING REMARKS Rear Admiral William C. Miller, USN Chief of Naval Research Ladies and gentlemen, officials and faculty of the University of Michigan, and distinguished colleagues from the international naval hydrodynamics community, I wish you a good morning. As Chief of Naval Research, as steward of the Navy's science and technology development, and as a former sailor and commanding officer in several classes of naval ships, I have a particular interest in naval hydrodynamics. Accordingly, it is my great pleasure to welcome you to this symposium dedicated to the advancement of the science and technology of naval hydrodynamics. The symposium is unique; it is the only professional gathering dedicated specifically to scientific understanding and technology of hydrodynamics in support of marine applications. Among you are the most prominent hydrodynamicists of the world. I am confident you will find the papers to be presented here uniformly excellent. Their selection proved a difficult task, given the number of quality papers submitted. This is the eighteenth symposium since the series was inaugurated in 1956. Each symposium in the series has been sponsored by the Office of Naval Research, the National Research Council, and a host institution. This year, we express our gratitude to our gracious host, the University of Michigan. The site for these symposia rotates between the United States and other countries, and over the years, seven different nations have hosted your meeting. This week, in keeping with the international flavor of this symposium, authors from 10 countries will be presenting 51 - papers-very strong evidence that the scientific communities are coming together to solve common hydrodynamics problems. The world is dramatically different today than when we began the series in 1956. We were then at the height of the cold war; now we are joined in a fervent hope that that period of international tension is nearing an end. Changes that would have seemed unthinkable only a few months ago are continuing to occur almost daily. Old barriers are falling; new challenges arising. Defense capabilities and requirements are being scrutinized in the light of new global realities. There is no question in my mind that the decade of the 1990s will exhibit a different international military presence than the decade that preceded it, and with those changes comes a corresponding adjustment to the distribution and focus of research and development activity. Political realignments and military changes notwithstanding, geography alone tells us that the United States will remain a maritime nation with economic and defense imperatives closely tied to free and unimpeded access to the sea lines of communication in order to pursue peaceful commerce. Also unchanged is the need of a maritime nation such as ours to pursue a broad program of science to better understand and utilize the seas that surround it. Joseph Conrad, that great chronicler of sea lore, once said, The sea never changes, arid its works, for all the talk of man, are wrapped i'' mystery. The sea probably has not changed much since Conrad penned those words, but advances in science and technology and development of new tools have helped to lift some of the mysteries associated with the seagoing trades. This is particularly true in naval hydrodynamics. With the emerging capability to understand and predict such complex processes as unsteady ship hydrodynamics, brought about by application of 1 supercomputers in both physical and numerical experiments, the field is ready for new and significant scientific breakthroughs to lead to improved propulsive efficiency, reduced ship motion, and more accurate tracking. For many problems in hydrodynamics, however, the level of understanding sufficient to drive technology application remains years away and, in Conrad's words, still Are wrapped in mystery. ~ It is the nature of scientific discovery that results frequently are a long time coming and often not clearly foreseen. Therefore, the Office of Naval Research has adopted the strategy of preserving our investment in fundamental research in the field of naval hydrodynamics, selecting the best intellects and the best ideas, while expressing our confidence that this long-term investment will pay valuable dividends. The University of Michigan's selection to be host this year reflects this investment philosophy, partly in recognition of university's work in free-surface hydrodynamics, funded by the University Research Initiative of the U.S. Department of Defense. Under this program, the Office of Naval Research provided financial support to the University of Michigan to pursue aggressive investigation into improving the state of knowledge of ship wakes. This initiative has been in place for four years now and has provided the means for developing and fielding a unique instrumentation system to quantify hydrodynamic features observed in both surface and subsurface wakes. Several papers to be presented at this symposium describe this instrumentation and associated research findings. In addition, a tour of facilities dedicated to this effort will be conducted tomorrow morning; it promises to be an eye opener for any who may have lingering doubts regarding whether there is significant science left to be pursued in the field of naval hydrodynamics. As this audience certainly appreciates, understanding the physical mechanisms present in ship wakes can have major influence on naval operations. In fact, the very title of this symposium proclaims its naval orientation. Certainly, knowledge of unsteady nonlinear ship motions is an elusive goal that may be in sight with new advances-such as prediction of "chaotic ship motion and unsteady ship wake-propulsion interaction. These advances should have an impact on commercial shipping as well as military operations, responding to the shared needs of all maritime nations. It is in the spirit of pushing back the frontiers in basic understanding of naval hydrodynamics that this symposium retains its preeminence. Papers are presented, discussions--oftentimes quite lively--are entertained, and professional and personal contacts are made or renewed, all with the intent of fostering open information exchange among scientific professionals. We anticipate that the result will be a focusing of efforts and minimization of unwarranted duplication, leading to achievement of shared objectives within the limited resources available. The papers to be presented cover seven topics: ship motions; ship hydrodynamics; experimental techniques; free-surface aspects; wave/wake dynamics; propeller/hull/appendage interactions; and viscous effects. I have been assured by the selection committee that they are uniformly excellent and will add to our pride in once again sponsoring this symposium. I trust that you too will enjoy them and will take home with you that sense of professional excitement and interaction you came here to enjoy. Thank you for your attention. You all have my personal best , , wishes for a most productive symposium.
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