Toward New Naval Platforms: A Strategic View of the Future of Naval Engineering (2019)

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65 5 Naval Engineering Science and Technology Infrastructure The National Naval Responsibility for Naval Engineering (NNR-NE) program’s programming and prioritizing of its third pillar, maintaining and supporting the infrastructure for naval-specific naval engineering (NE) research and development (R&D), can also be guided by the “lead, leverage, and monitor” construct. Success in furthering the first pillar of the NNR-NE, the leading and leveraging of the R&D needed to satisfy the future Navy’s unique and critical NE needs, requires an infrastructure of experimental facilities and modeling and simulation resources. Investments in the maintenance, invigoration, and advancement of this physical and computational infrastructure are also critical to building and developing the NE educational and research pipeline to ensure a skilled and talented NE workforce. Because the NNR-NE does not own, manage, or program the capital investments made in much of this infrastructure, especially large- scale experimental facilities, it must find ways to ensure the infrastructure’s availability and suitability for conducting and integrating needed NE R&D and for sustaining and strengthening the NE workforce. This chapter discusses the importance of both forms of science and technology (S&T) infrastructure—experimental and computational—to the Navy’s NE enterprise and considers the challenges and choices the NNR-NE faces in ensuring its availability and suitability for meeting the future Navy’s NE needs. The array of S&T infrastructure needed for R&D is as varied as hydrodynamics and structures to propulsors and power creates a resource availability and allocation challenge for NNR-NE. As discussed next, this challenge can be vexing when it comes to ensuring the availability of large- scale experimental assets. Small-scale testing facilities and computational

66 TOWARD NEW NAVAL PLATFORMS resources are providing alternatives to large-scale facilities, but they too can present technical and resource-related challenges, including a demand for complementary physical testing infrastructure. CHANGING ROLE OF EXPERIMENTAL INFRASTRUCTURE The NNR-NE supports experimental research by university faculty con- ducted using the testing facilities of the Navy’s Warfare Centers (WCs), other federal government agencies, universities, and research institutions outside the country. The chapter addendum contains an inventory of the numerous experimental facilities available for outside (government and private sector) researcher use at the Naval Surface Warfare Center (NSWC). The facilities in the Navy’s WCs have the advantage of allowing experi- ments close to scale and enabling valuable collaborations among university- affiliated researchers and WC personnel. However, a significant challenge for researchers working on NNR-NE projects is covering the use fees charged by WC facilities, as these charges usually include large overhead costs. Investigators who do not reside near the WC will also need to make extended-stay travel arrangements when using the facilities, adding to the expense of experiments. A compounding factor is the need for researchers to obtain security clearances to access the WCs, which can delay use of the test facilities and sometimes preclude access by non-citizens. These factors, in turn, can have the effect of reducing the overall use of the WC facil- ity, which means that overhead costs are divided among a small number of researchers, further disadvantaging university researchers working on small-budget NNR-NE projects. Whereas underutilized WC facilities can often generate the user-based income needed to keep equipment running; the revenues earned may not be sufficient to finance equipment upgrades, or to operate the facility with sufficient frequency to build the technical capabilities of testing personnel. Consequently, the facilities can become technologically stagnant, which further reduces their value to researchers. By way of example, data on the average annual usage and income from user fees of the hydrodynamics fa- cilities operated by the NSWC Carderock Division from fiscal years 2015 to 2018 are presented in Table 5-1. The data show the low usage (averaging about 21 hours per week) and resulting low income generated by important facilities such as the Large Cavitation Channel. The main alternatives to large-scale WC facilities and other government assets for experimental research are smaller-scale university facilities and large-scale testing centers operated abroad. While there are some examples of large-scale university facilities that remain in operation in the United States, such as hydrodynamic testing facilities at the University of Michi- gan and the University of Minnesota, most university facilities are small in

NAVAL ENGINEERING SCIENCE AND TECHNOLOGY INFRASTRUCTURE 67 scale, due in part to limitations on space. Such facilities may be funded by government grants or by the institution itself (e.g., startup funds for young investigators, capital improvement funds). For example, competitive grants for the construction and upgrading of facilities and their equipment are awarded by the National Science Foundation (NSF) (e.g., Major Research Instrumentation Program) and the U.S. Department of Defense (DOD) (University Research Instrumentation Program). In the case of experimental facilities that have primarily naval application, the Office of Naval Research (ONR) and other units of the Navy may provide support for their develop- ment, including grants by the NNR-NE for smaller-scale facilities. While tests conducted using smaller-scale facilities may not replicate the physics of the full-scale environment, the testing can nevertheless be valuable for validating computational models. Another advantage is that these local facilities can provide immediate access to researchers, who also incur lower overhead fees. Nevertheless, it is fair to question whether it is efficient for NNR-NE to spread its experimental infrastructure investments, even if individual outlays are relatively small, across myriad testing facilities TABLE 5-1 Average Annual Hours of Use and Income Generated from User Fees, Hydrodynamics Facilities of the Naval Surface Warfare Center, Fiscal Years 2015 to 2018 Hydrodynamics Facility Income (thousands) Usage (hours) Carriage 1 370 803 Carriage 2 706 1,144 Carriage 3 170 301 Carriage 5 257 163 140ʹ Basin 27 705 MASK 1,134 2,102 Rotating Arm 210 483 8ʹ×10ʹ Wind Tunnel 108 406 12ʺ Water Tunnel 1 50 24ʺ Water Tunnel 42 146 36ʺ Water Tunnel 251 307 LCC 1,710 1,110 Circulating Water Channel 83 371 NOTE: LCC = Large Cavitation Channel; MASK = Maneuvering and Seakeeping Basin. SOURCE: Personal communication with NSWC-CD test facility staff.

68 TOWARD NEW NAVAL PLATFORMS because of the potential for redundancy and limited access by researchers from other institutions. There is the possibility too that these smaller fa- cilities may become underutilized, or even abandoned, as researchers leave institutions or change their research direction. For research projects that require the scale and test features comparable to those of WC facilities, the investigator may partner with overseas institu- tions that operate facilities with the needed capabilities. For example, the Maritime Research Institute Netherlands1 operates several large-scale facili- ties that are comparable to those at NSWC Carderock (see Box 5-1) and the National Research Council of Italy operates INSEAN,2 a naval architecture and marine engineering research institute that has invested in a large circu- lating water channel and two cavitation channels. Other examples are the Lir National Ocean Test Facility Wave Tank in Ireland3 and the FloWave Ocean Energy Research Facility in Scotland.4 A comprehensive list of large-scale hydrodynamic test facilities has been assembled by the International Towing Tank Conference.5 This inven- tory shows that some countries operate or are building test facilities with capabilities not offered by WC facilities. For example, Russia and China, among other nations (primarily in Europe), have built ice basin facilities to 1 See https://www.marin.nl. 2 See http://www.insean.cnr.it. 3 See http://www.lir-notf.com. 4 See https://www.flowavett.co.uk. 5 See https://ittc.info/facilities. BOX 5-1 Maritime Research Institute Netherlands Hydrodynamics Facilities • Depressurized Towing Tank (upgraded 2011) • Deep Water Towing Tank (upgraded 1951) • Concept Basin (upgraded 2015) • Large Cavitation Tunnel (upgraded 1966) • Offshore Basin (upgraded 2016) • Seakeeping and Maneuvering Basin (upgraded 2017) • Shallow Water Basin (upgrade unspecified) • Ship Maneuvering Simulator (upgrade unspecified) • High-Speed Cavitation Tunnel (upgrade unspecified) SOURCE: International Towing Tank Conference (https://ittc.info/facilities).

NAVAL ENGINEERING SCIENCE AND TECHNOLOGY INFRASTRUCTURE 69 accommodate research on vessel icebreaking capabilities as a warming cli- mate has opened previously inaccessible waterways. The National Research Council of Canada operates an ice tank in Newfoundland that is being used for testing of icebreaker designs, including those that may be employed by the U.S. Coast Guard.6 Researchers may choose to use such foreign facilities because they of- fer capabilities not found in the United States and/or because they may be accessed at less expense and with fewer security and clearance restrictions. While the latter advantages may appeal to researchers working on projects with constrained budgets, one can question whether sending experimental- ists to test facilities overseas is consistent with furthering the NNR-NE’s mission to develop the U.S. NE workforce and in meeting naval-relevant S&T needs. Even in cases where the research is unclassified, the content may be sensitive enough that it may not be desirable to perform tests abroad that would be operated and observed by foreign nationals. As computational resources become faster, less expensive, and more nimble and capable, large investments in domestic experimental facilities may become more difficult to justify. At the same time—and as discussed next—until model-based engineering is proven unequivocally accurate, experiments to validate the fidelity of computational modeling may be required and necessitate the maintenance of a hybrid experimental-compu- tational research paradigm. CHANGING COMPUTATIONAL CAPABILITIES As computing power has increased along with improvements in high- performance computing architectures, the entire DOD enterprise has seen a shift toward the use of modeling and simulation to drive the design, development, and testing of highly complex military systems. Advanced computing and modeling capabilities offer the potential for holistic evalua- tion in accelerated time scales and faster delivery of capability to the fleet. The trend toward a more digital representation of naval platform ca- pabilities presents both opportunities and challenges. The study committee heard numerous accounts from the shipbuilding industry of the use of a digital “twin” and model-based systems engineering (MBSE) to enable a more efficient, highly integrated systems engineering life cycle for naval platforms (see Appendix A). From an overall cost standpoint, a true digital twin promises significant savings in time and materials to Navy platform programs. An integrated MBSE capability can aid design teams in identify- ing issues earlier in the life cycle, adapting to changing requirements with 6 See https://nrc.canada.ca/en/research-development/nrc-facilities/ice-tank-21-m-research-facility.

70 TOWARD NEW NAVAL PLATFORMS ease, and validating the performance of new baselines through consistent, repeatable test conditions. However, while advances in computational capabilities promise to compress ship design, development, and test schedules, there is good reason to believe they will never fully replace experimental testing and may even create a need for more sophisticated, higher precision, and larger-scale test- ing facilities. For example, in recent years computational fluid dynamics (CFD) has advanced along two complementary and overlapping fronts relevant to naval engineering: (1) modeling and simulation of complex multi-physics, multi-scale phenomena, such as wave breaking, air entrain- ment, and flow cavitation; and (2) incorporation of increasingly compli- cated geometries, motions, and mechanisms in greater spatial and temporal scales (e.g., 6 degrees of freedom motions and maneuvering of realistic hull plus appendages and propulsors in realistic seas and wind). In the former case, high resolution and precision whole-field 4-dimension (volume plus time) measurements applied to canonical/“idealized” problems provide direct quantitative comparisons to CFD that are essential for assessing and validating the inherent assumptions, modeling fidelity, and computational predictions of CFD. In the latter case, large-scale CFD is becoming increas- ingly competitive with traditional tank tests. However, modeling/simulation can only approximate reality. Integrating multiple components, even if fully modeled, can yield unexpected, emergent behavior, and as scales and physi- cal complexities increase (e.g., nonlinearities, unsteadiness, compressibility, compliant non-smooth surfaces, and fluid–structure interactions), large physical facilities and tests may become essential for both complementing and validating CFD predictions (see Box 5-2 for an illustration). IMPLICATIONS FOR NNR-NE’S “LEAD, LEVERAGE, AND MONITOR” FUNCTIONS A number of challenges that NNR-NE faces for ensuring the availability and suitability of the NE research and testing infrastructure have already been identified. What these challenges suggest is that the physical experi- mental infrastructure needed for NE R&D and workforce development is changing but not going away. While NNR-NE supports the design and devel opment of infrastructure at the smaller scale (often in university set- tings), the nature of NE research can often require large-scale infrastructure with unique capabilities. Solutions, therefore, will be needed to overcome impediments to the development and use of the needed physical infrastruc- ture and for exploiting opportunities for leveraging existing experimental assets. As a first step in the development of such solutions the committee rec- ommends that ONR should undertake a thorough inventory and assessment

NAVAL ENGINEERING SCIENCE AND TECHNOLOGY INFRASTRUCTURE 71 of NE testing infrastructure needs and capabilities, large and small, in the Navy, elsewhere in DOD, at universities, in the private sector, and at institu- tions abroad (Recommendation 5-1). The inventory and assessment should consider options for making greater use of relevant testing infrastructure from within and outside DOD, including the assets of other government agencies. For example, the U.S. Department of the Interior manages a large wave and tow tank facility, the Oil and Hazardous Materials Simulated Environmental Test Tank, that can be booked by university researchers and has many capabilities that overlap with NNR-NE needs. Consideration should also be given to the applicability of small-scale testing facilities that may exist in university settings but that are associated with faculties not traditionally viewed as part of the NE enterprise, such as the wave tanks, towing basins, and flumes used by researchers in civil and environmental engineering departments. BOX 5-2 The Complementary Role of Experimental and Computational Capabilities for Naval Engineering as Exemplified by Cavitation Dynamics Unsteady cavitation is known to cause noise, vibration, and erosion of marine lifting bodies. Hence, it is important to understand the cause of unsteady cavity shedding. Until recently, researchers believed the formation of the re-entrant jet that initiates at the rear of the cavity and moves upstream is the primary driver of this phenomenon, and most computational fluid dynamics (CFD) models assume incompressible flow. X-ray densitometry experiments have shown that another important driver is the formation and propagation of shock waves, caused by the drop in the local sound speed of the liquid-vapor mixture. CFD models must therefore account for the effect of flow compressibility in addition to the complex multiphase and multi-scale dynamics of cavitation. The results also demonstrate the need for complementary experimental and computational modeling, as it is very difficult to simultaneously measure the spatial and temporal distribution of vapor fraction, velocity, and pressure distribution, but experiments are also needed to understand the validity of the fundamental assumptions in the numeri- cal models. To add to the complexity, recent experiments have also shown that structural vibrations can also drastically modify the cavity shedding frequency and resulting spectral response through nonlinear fluid–structure interaction. Preliminary results also suggest that it may be possible to control the cavitating response by applying controlled, small-amplitude structural vibrations at the proper frequency. The fluid–structure interaction response is very challenging to scale in laboratory experiments because of the need to properly scale the material, structure, and flow conditions in addition to the controller algorithm. Simultaneously, understanding of the physics is critical to developing the correct models to simulate the response.

72 TOWARD NEW NAVAL PLATFORMS Informed by this recommended inventory and assessment of testing needs and capabilities, the committee recommends that ONR should use the “lead, leverage, monitor” framework to guide NNR-NE’s efforts to ensure the availability and suitability of the NE R&D infrastructure (Rec- ommendation 5-2). Table 5-2 identifies opportunities where the NNR-NE can take the lead in ensuring the needed experimental capacity is available to NE re- searchers and students and where it can leverage the capabilities of other organizations. In fulfillment of its lead function, NNR-NE should consider convening working groups of NE researchers to advise the WCs on facility maintenance needs, capability gaps, and opportunities for upgrades. Such an effort could be patterned after the Naval Sea Systems Command’s Re- quest for Information for its Shipyard Infrastructure Optimization Program. Consideration should also be given to identifying ways to make university facilities constructed with NNR-NE funding or performing NNR-NE work more accessible to researchers from other institutions. ONR might explore the idea of establishing a consortium of these academic facilities by funding them to set aside a small fraction of their operational time for shared-use operations. ONR needs to be systematic in its choices about when and how it should lead, leverage, and monitor for the purpose of ensuring that the adequate experimental infrastructure is available for the NE enterprise. Ac- cordingly, the committee further recommends that ONR should develop a comprehensive plan for increasing the availability and utilization of needed S&T experimental infrastructure, including making large-scale facilities more affordable to NNR-NE researchers and smaller-scale facilities less redundant and more open to shared use (Recommendation 5-3). A plan to make the Navy’s large-scale experimental infrastructure more cost and security accessible to university researchers may require in- novations in facility business models, perhaps inspired by the approaches of other government agencies. Consideration might be given, for instance, TABLE 5-2 Where NNR-NE Can Lead, Leverage, and Monitor to Ensure That R&D Instructure Is Available and Suitable for NE Needs Lead Leverage Monitor • User group of academic investigators using Warfare Center (WC) experimental infrastructure • Consortium of National Naval Responsibility for Naval Engineering university facilities • WC facilities • Commercial test centers • Private and other government infrastructure • U.S. Department of Defense high-performance computing • Test capability and access provided by international facilities

NAVAL ENGINEERING SCIENCE AND TECHNOLOGY INFRASTRUCTURE 73 to the practices employed by the U.S. Department of Energy (DOE) and NSF in managing and funding their large-scale facilities and equipment. As an example, DOE’s National Nuclear Security Administration and Of- fice of Science administer the National Laser Users’ Facility Program to provide access to and funding for the use of the OMEGA Laser Facility at the University of Rochester.7 The program reaches out to the community of academic and industrial researchers who are interested in conducting high-energy-density physics and inertial confinement fusion research at the facility, and has the goal of providing the research experience necessary to maintain a cadre of trained scientists to meet the country’s future needs in these S&T areas. It merits noting that the OMEGA facility also holds regular user workshops to disseminate results and foster collaborations, and it convenes scientific advisory committees whose members discuss maintenance and formulate ideas for facility upgrades. Addendum The following NSWC Carderock Division facilities are available for use by outside sources (both government and private sector) through Coopera- tive Research and Development Agreements and Work for Private Parties Agreements.8 • Acoustic Research Detachment • Advanced Ceramics Laboratory • Advanced Electrical Machinery Systems Facility • Advanced Shipboard Machinery Development Facility • Air Conditioning and Refrigeration Test Facility • Anechoic Flow Facility • Biotechnology Laboratories • Boiler Components Test Facility • Cargo/Weapons Elevator Land Based Engineering Site • Center for Innovation in Ship Development • Circulating Water Channel • Combatant Craft Department • Compressed Air System Facility • Data Collection and Calibration Facility • David Taylor Model Basin • Deep Submergence Pressure Tank Facility • Diesel Engine Development Facility 7 See https://www.grants.gov/web/grants/view-opportunity.html?oppId=312481. 8 See https://www.navsea.navy.mil/Home/Warfare-Centers/NSWC-Carderock/What-We-Do/ Laboratories-and-Research-Facilities/List-of-Laboratories-and-Research-Facilities.

74 TOWARD NEW NAVAL PLATFORMS • Dosimetry Laboratories • Electrical Power Technology Facility • Electrochemical/Battery Laboratories • Environmental Protection Laboratories • Explosives Test Pond • Fatigue and Fracture Laboratories • Fire Tolerant Materials Laboratories • Fox Island Laboratory • Fuel Cell Laboratory • Gas Turbine Development Facility • Hull, Mechanical, and Electrical Systems Live Fire Test Facility • Industrial Technology Laboratory • Infrared Systems • Large Cavitation Channel • Large Scale Grillage Test Facility • Machinery Acoustic Silencing Laboratory • Machinery Automation and Controls Facility • Magnetic Fields Laboratory • Magnetic Materials Laboratory • Maneuvering and Seakeeping Basin • Manufacturing Technology Laboratory • Marine Coatings Laboratories • Marine Corrosion Control and Evaluation Laboratories • Marine Organic Composites Laboratories • Materials Characterization and Analysis Laboratory • Metal Spray Forming Laboratory • Mission Support Facility • Network Integration and Fiber Optics Facility • Nondestructive Evaluation Laboratories • Power Generation Test and Evaluation Facility • Radar Imaging Modeling System • Research Vessel Lauren Reverse Osmosis Test Facility • Rotating Arm Facility • Ship Materials Technology Center • Ship Motion Simulator Land Based Test Site • Ship Virtual Prototyping Laboratory • Shock Trials Instrumentation • Signature Materials Laboratory • Small Gas Turbine Test Facility • South Florida Testing Facility • Southeast Alaska Acoustic Measurement Facility • Steam Propulsion Support Facility • Steam Propulsion Test Facility

NAVAL ENGINEERING SCIENCE AND TECHNOLOGY INFRASTRUCTURE 75 • Structural Dynamics Laboratory • Structural Evaluation Laboratory • Subsonic Wind Tunnel • Survivability Engineering Facility • Torpedo Strikedown Lift System Land Based Test Site • Undersea Vehicle Sail and Deployed Systems Facility • Underwater Explosions Test Facility • USNS HAYES Oceanographic Research Ship • Welding Process and Consumable Development Laboratories