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An Assessment of Naval Hydromechanics Science and Technology 5 Integration with and Transition to Higher-Budget-Category Programs As defined by ONR, the hydromechanics area consists largely of 6.1 and 6.2 efforts, as shown in Figure 2.1 and Table 2.1 in Chapter 2. For example, in FY99, the total funding of $24.9 million consisted of $12 million from 6.1 and $10.4 million from 6.2, with the small balance from either 6.3 or non-Navy sources. In fact, FY99 is an anomaly in that the 6.2 funding was substantially higher than in any of the preceding 5 years. As explained earlier, this increase was due to a one-time infusion of an additional 52 percent of core 6.2 funds in FY99, which was directed at short-term applications. Over the preceding 5 years, Navy efforts in hydromechanics were funded largely in category 6.1. If such 6.1 efforts are to ultimately significantly increase naval capabilities, they will need to stimulate new 6.2 and 6.3 programs for developing and demonstrating advanced technology to achieve a readiness level appropriate for transition to acquisition programs, and they will also need to be responsive to the research opportunities identified by the 6.2/6.3 efforts. The 6.1 work will be most effective if it contains a balance of exploratory work on very new ideas and very fundamental work in response to opportunities and challenges identified in higher-budget-category programs. The need for this sort of balance is particularly acute in hydromechanics, which deals with matters that have a large impact on the overall characteristics of ship and submarine platforms: stealth, speed, payload capability, seakeeping/maneuverability, and cost. This means that robust 6.2/6.3 technology development and demonstrations programs, with their emphasis on advanced concepts, are required to underpin the transitioning of significant technology advances to higher budget categories. In addition, significant advances in hydromechanics will require a thorough understanding of the underlying physics as it applies to potential concepts for signature reduction, drag reduction, and other improvements; this is the proper realm of 6.1 research. A long-term 6.2 and 6.3 technology development and demonstration program focused on reasonably well-defined advanced concepts also identifies opportunities and serves as a testing ground for research results. This feedback from technology development to fundamental research is critically important to advancing the state of the art. Two examples will illustrate this point: Significant reductions in the sonar self-noise of surface ship bow domes and submarine sonar domes have been achieved over the last several years. The fundamental physics of structural excitation
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An Assessment of Naval Hydromechanics Science and Technology by turbulent boundary layers has been funded by ONR for many years. This led to an understanding of exponential attenuation of evanescent (nonradiating) hydrodynamic wave numbers, which when applied to the concept of using materials that were inefficient radiators and good transmitters led to rubber- or glass-reinforced plastic domes. Currently, a great deal of fundamental hydromechanics research is focused on computational fluid dynamics (CFD) and the treatment of unsolved problems associated therewith: turbulence, separation, cavitation, and free-surface behavior, including bow and transom wave breaking. Such research is important since, clearly, CFD will become more powerful in the years ahead. However, general solutions to the unsolved problems are not imminent, and even if they were, they would not produce advanced platform concepts. A vital strength of such research is its ability to develop techniques that are adequate for the analysis of specific concepts and to perform such analyses. Without clearly defined concepts, there is a danger that CFD research will not be as effective as it otherwise could be (e.g., the study of highly separated flows is a challenging problem but is not particularly relevant to concepts designed to avoid or limit separation). Certainly ONR and the Naval Sea Systems Command 05H, which includes the Hydrodynamics/ Hydroacoustics Technology Center, recognize the importance of advanced concepts. In their presentations to the committee, both organizations emphasized the importance of concept development, with specific reference to advanced shaping, advanced appendages, advanced propulsion, and advanced flow control techniques. Unfortunately, the committee could find no persuasive evidence that there is a currently planned 6.2/6.3 effort to create advanced platform concepts. None of the presentations reported any concerted efforts to explore advanced concepts, either at a subsystem or total system level. Rather, the emphasis is on transitioning design tools for current concepts, which are based primarily on computational fluid dynamics. Improvements in such tools will undoubtedly transition (i.e., be used by designers) once they have been adequately validated; such transitions are important and will at least partially satisfy the perceived pressure for near-term results. However, as noted above, these tools alone are unlikely to lead to significant advances in platform capability. If successful, their largest impact will be to reduce development cost and time. It should be emphasized that there is no lack of need for advanced technology nor any lack of desire to produce it. In the 1997 NSB study Technology for the United States Navy and Marine Corps, 2000-2035,1 stealth was identified as a fundamental attribute for submarines. Although it was not such a priority for surface ships, signature reduction was considered to be necessary and cost-effective. Additional emphasis on stealth was articulated by the Program Executive Office-Submarines, which called the art and science of designing and building quiet submarine propulsors one of its crown jewels. Moreover, greater affordability —that is, more capability per unit cost—is always needed, and it is an area where hydromechanics can have a significant impact. In the laboratory arena, a recent review by the NSWCCD gave prominence to signature and silencing systems and hull forms and propulsors as its core assets. Yet there does not appear to be an integrated 6.2/6.3 program to bring appropriate concepts to fruition. One reason for the lack of an integrated 6.2/6.3 program that includes development of advanced platform concepts may be the persistent lack of adequate funding. Table 5.1 and Figure 5.1 show funding for 6.2/6.3 Navy Department ship and submarine technology funding from FY82 through FY99. The funding shown in Figure 5.1 is the total of up to four program elements in each fiscal year: 0602121N, currently titled surface ship and submarine technology; 0602323N, now defunct, but titled submarine technology when it existed; 0603508N, which used to be titled ship propulsion system (advanced); and 0603573N, titled electric drive when it was a 6.3 program. The total Department of the Navy 6.2/6.3 investment for all ship and submarine technology in the FY99 President's Budget was about $100 million per year, which covers efforts in structures, internal machinery, topside signature reduction, and electromagnetic compatibility as well as hydromechanics. Although this level of funding is actually higher than representative annual investments for the past two decades, when the 6.2/6.3 effort averaged about $70 million per year, it does not seem adequate to conduct the type of technology demonstrations required for advanced platform concepts. 1 Naval Studies Board, National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force, Vol. 6, Platforms. Washington, D.C.: National Academy Press.
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An Assessment of Naval Hydromechanics Science and Technology TABLE 5.1 6.2/6.3 Funding for Department of the Navy Ship and Submarine Hull, Machinery, and Electrical Technology in Then-Year Dollars (millions of dollars) Program Element Year 0602121N Various—Ship/Submarine 0602323N Submarine Technology 0603508N Ship Propulsion System 0603573N Electric Drive Total FY82 41.0 0.0 12.6 0.0 53.6 FY83 NA NA NA NA NA FY84 31.1 0.0 41.5 13.4 86.0 FY85 30.2 0.0 47.7 0.0 77.9 FY86 25.3 0.0 30.7 9.8 65.8 FY87 12.5 12.4 10.0 9.8 44.7 FY88 13.0 14.1 14.5 9.0 50.6 FY89 13.3 14.5 14.8 14.0 56.6 FY90 13.8 15.0 0.0 32.1 60.9 FY91 16.0 16.7 0.0 53.8 86.5 FY92 32.0 17.8 4.5 0.0 54.3 FY93 50.1 17.9 4.5 0.0 72.5 FY94 19.3 14.6 3.4 0.0 37.3 FY95 19.9 14.6 3.2 0.0 37.3 FY96 62.9 0.0 18.0 0.0 80.9 FY97 48.7 0.0 31.6 0.0 80.3 FY98 50.4 0.0 49.7 0.0 100.1 FY99 55.5 0.0 52.9 0.0 108.4 SOURCE: All data shown in Table 5.1 are based on the committee's use of documents in the series Defense Department Appropriations for Fiscal Year [1982-1999], Superintendent of Documents, U.S. Government PrintingOffice, Washington, D.C. Historically, it appears that the Navy has relied on acquisition program funding to effect large-scale technology demonstrations. In addition, NSWCCD, NUWC, and the Applied Research Laboratory at Pennsylvania State University (ARL/PSU) all noted that the current and projected levels of S&T funding are inadequate to maintain a core capability, to carry out the required fundamental research, and to provide incentives for bright, young graduates to enter the field. For the last two decades, this shortfall in S&T funding has been compensated for, at least in part, by the influx of funds from acquisition programs and, in the case of submarines, DARPA.
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An Assessment of Naval Hydromechanics Science and Technology FIGURE 5.1 Department of the Navy 6.2/6.3 ship and submarine HM&E technology funding. SOURCE: All data shown in Figure 5.1 are based on the committee's use of documents in the series Defense Department Appropriations for Fiscal Year [1982-1999], Superintendent of Documents, U.S. Government PrintingOffice, Washington, D.C. There are two types of acquisition funding: one is funding for the development and procurement of major warships; the other is 6.4 funding not directly associated with major acquisitions. There are several difficulties associated with relying on major acquisition funds for technology development and demonstration as well as for maintaining core capabilities. Acquisition funding for the first in a class of new warships, although it is large, is in category 6.4 or higher, in RDT&E or in procurement (ship construction (building and conversion), Navy—SCN). Additionally, the funding is apportioned to the individual acquisition programs keyed to the fiscal year of the lead ship construction contract and usually becomes available, ostensibly to support the total system design, 2 to 3 years before that fiscal year (see Figure 2.2). In general, the funding arrives too late to trigger significant new research and too late to transition anything but very mature work; it cannot be relied on for the high-risk technology demonstrations that are the precursors to large advances. Nonetheless it has some beneficial effects: it brings about some technology transition, some of which was no doubt serendipitous; it encourages frequent communications between research staff and engineering personnel assigned to support the design of a new ship; it provides input from ship designers to ONR on their selection of technology efforts, thereby ensuring their integration in the short term; and it enables the laboratories to remain manned and active. However, there has been a long interval between new classes: for aircraft carriers
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An Assessment of Naval Hydromechanics Science and Technology almost 40 years, and for submarines and destroyers 10 to 15 years. With the current levels of S&T funding, there will be long, dry periods that can prove disastrous for maintaining a first-class research capability, for advancing the state of hydromechanics technology, and for being able to recruit graduates. Even in the best of times, it is questionable policy to rely on major acquisition funds for the advancement of technology; it is certainly not good policy now. Category 6.4 funds not associated with major acquisitions do offer greater opportunity for technology demonstration. In the 1970s, the Small Waterplane Area Twin Hull (SWATH) ship concept was matured and developed into the Navy's first stealth surface ship, Sea Shadow, by the application of 6.1 and 6.2 funding, supplemented by funding from a then 6.3 program called “Conform.” This program would now be funded by a 6.4 line. The Conform program was run by ship design managers who had direct responsibility for adapting the technology into advanced design platforms. The Conform program had its origin in the mid- to late 1960s, when the Office of the Secretary of Defense (OSD) required all major acquisitions to undergo three systematic phases called concept formulation (Conform): (1) concept exploration and concept development, (2) contract definition, and (3) prototype production. The U.S. Navy was required to go through this process for the LHA and DD 963 classes. Concept formulation was started for the successor submarine class to the SSN 637. This evolved into the preliminary design for the SSN 688 class, which was procured in the old fashion. It became obvious during the submarine Conform program that there was a serious disconnect between S&T and R&D and the design process. The solution was obvious for future designs: a continuing effort of advanced concept exploration funded as a (then) 6.3 line. This proposal was approved and funded for several years for submarines. It became unfunded but survived as the surface ship 6.3 line described above. The Navy currently has a submarine technology program funded in acquisition category 6.4. This program is devoted to all aspects of submarine technology—communications, combat systems, weapons, internal machinery, and hydromechanics. Funding for this program is approximately $40 million per year; current efforts are largely devoted to near-term improvements for the new attack submarine (NSSN), but future efforts will be more aggressive. The program affords ONR an opportunity to formulate a 6.2/6.3 program wherein a substantial amount of technology demonstration could be conducted with 6.4 funds. The fact that the program was not mentioned in any of the presentations to the committee is another indication that in the hydromechanics area, integration with higher-category programs could be improved. Another reason for the lack of an integrated 6.2/6.3 program aimed at advanced platform concepts—and it may also explain the lack of funds—may be a lack of commitment to pursue the concepts to their logical conclusions. There is no shortage of advanced concepts: trimarans, tumble-home monohulls, high-speed sealift vehicles, planing craft, and submarine platforms with minimal or no appendages, to name a few. Many of these concepts have been postulated for a number of years. All of them entail unknowns in hydromechanics, and most would require advanced concepts at the subsystem level (i.e., shaping, flow control, appendages, and propulsors) if useful vehicles are to result. Two examples at the subsystem level follow: When submarines increase their speeds flow-induced noise becomes a major cause of detection and classification by threat sonars. There are a number of contributors to flow-induced noise, including the sail, flood ports, control surfaces, and other discontinuities along the hull. During maneuvers, the acoustic levels are much higher owing to separated flows and enhanced flow distortions. The basic reasons are generally understood, but the flow-acoustic interactions are complex; concepts for noise control are needed if these interactions are to be quantified in a highly relevant manner. For example,
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An Assessment of Naval Hydromechanics Science and Technology one concept might be to eliminate the sail. While this would of course create a need for other advances, it would eliminate a significant source of radiation noise and reflectivity to active sonar. Evolving mission requirements necessitate hull and appendage geometries that often set practical limits to the achievement of important performance parameters. There has been renewed interest in polymer ejection to reduce drag and noise. If they can be further developed and demonstrated at a practical level, the required high-speed signature and maneuvering capabilities may be achieved at much lower acquisition and life-cycle cost. There are many other examples of the need to pursue advanced concepts in a disciplined way. Yet there was no integrated 6.2/6.3 plan presented to the committee to pursue any one of these concepts to the point where it could be shown to be potentially successful, or alternatively, not worth pursuing further. If significant increases in basic platform capabilities are to be made, they will come only from the pursuit of advanced concepts. It is largely the magnitude of the potential increases in platform capabilities that determines the amount of funding that will be made available. Without a credible, integrated 6.2/6.3 plan to achieve such capabilities, the funding is likely to be inadequate.
Representative terms from entire chapter: