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At least 1,117 records · Page 62

Multi-disciplinary coupling for integrated design of propulsion systems

Effective computational simulation procedures are described for modeling the inherent multi-disciplinary interactions for determining the true response of propulsion systems. Results are presented for propulsion system responses including multi-discipline coupling effects via (1) coupled multi-discipline tailoring, (2) an integrated system of multidisciplinary simulators, (3) coupled material-behavior/fabrication-process tailoring, (4) sensitivities using a probabilistic simulator, and (5) coupled materials/structures/fracture/probabilistic behavior simulator. The results show that the best designs can be determined if the analysis/tailoring methods account for the multi-disciplinary coupling effects. The coupling across disciplines can be used to develop an integrated interactive multi-discipline numerical propulsion system simulator.

Chamis, C. C.↗

The Second Annual International Space University Alumni Conference

The papers presented at the conference reflect the multidisciplinary nature of the International Space University (ISU) and its alumni. The first papers presented hold special relevance to the design projects, and cover such topics as lunar-based astronomical instrumentation, solar lunar power generation, habitation on the moon, and the legal issues governing multinational astronauts conducting research in space. The next set of papers cover various technical issues such as project success assessment, satellite networks and space station dynamics, thus reflecting the diverse backgrounds of the ISU alumni.

Johnson, Les↗

An innovative approach to space education

At present, Canada does not have enough scientists to be competitive in the global economy, which is rapidly changing from a reliance on natural resources and industry to information and technology. Space is the final frontier and it is a multidisciplinary endeavor. It requires a knowledge of science and math, as well as non-science areas such as architecture and law. Thus, it can attract a large number of students with a diverse range of interests and career goals. An overview is presented of the space education program designed by Canadian Alumni of the International Space University (CAISU) to encourage students to pursue studies and careers in science and technology and to improve science literacy in Canada.

Marton, Christine↗

Mapping analysis and planning system for the John F. Kennedy Space Center

Environmental management, impact assessment, research and monitoring are multidisciplinary activities which are ideally suited to incorporate a multi-media approach to environmental problem solving. Geographic information systems (GIS), simulation models, neural networks and expert-system software are some of the advancing technologies being used for data management, query, analysis and display. At the 140,000 acre John F. Kennedy Space Center, the Advanced Software Technology group has been supporting development and implementation of a program that integrates these and other rapidly evolving hardware and software capabilities into a comprehensive Mapping, Analysis and Planning System (MAPS) based in a workstation/local are network environment. An expert-system shell is being developed to link the various databases to guide users through the numerous stages of a facility siting and environmental assessment. The expert-system shell approach is appealing for its ease of data access by management-level decision makers while maintaining the involvement of the data specialists. This, as well as increased efficiency and accuracy in data analysis and report preparation, can benefit any organization involved in natural resources management.

Hall, C. R.↗

Operations summary for the convection and moisture experiment (CAMEX)

During the fall of 1993, NASA sponsored a field program called the Convection and Moisture Experiment (CAMEX) at Wallops Island, Virginia. CAMEX was a multidisciplinary experiment design to measure the three dimensional moisture fields over Wallops Island and to characterize the multifrequency radiometric signature of tropical convection over the Gulf Stream and southeastern Atlantic Ocean. This document summarizes the daily CAMEX activities, including ground and aircraft (NASA ER-2) operations, and includes 'quick-look' summaries of data acquisition along with data examples provided by the various CAMEX PI's.

Griffin, V. L.↗

Overview of Langley systems studies

Late in 1990, the NASA Systems Integration Group began functioning and the aircraft systems studies entered a second phase. This group proposed tightly coordinated Ames/Langley/Lewis/industry studies that would address a series of tasks to evaluate progress, recommend appropriate direction, and emphasize changes in technology elements based on system level payoffs and potential success assessments. Based on technical and economic assessment studies of the High Speed Civil Transport (HSCT) to date, Mach 2.4 was chosen as the primary focus for the High Speed Research Program with Mach numbers 2.0 and 1.6 being backups in case of technology shortfalls. Langley has established an interdisciplinary team to strengthen the multidisciplinary aspects of aircraft design and analysis. The vehicle focus of this team is the HSCT. At Langley, early HSCT studies focused on turbojet powered aircraft. They also concluded that variable sweep wing concepts require 50/50 subsonic/supersonic to payoff for Mach 3.0 concept. Progress has been good in low sonic boom concepts.

Dollyhigh, Samuel D.↗

Fusion interfaces for tactical environments: An application of virtual reality technology

The term Fusion Interface is defined as a class of interface which integrally incorporates both virtual and nonvirtual concepts and devices across the visual, auditory, and haptic sensory modalities. A fusion interface is a multisensory virtually-augmented synthetic environment. A new facility has been developed within the Human Engineering Division of the Armstrong Laboratory dedicated to exploratory development of fusion interface concepts. This new facility, the Fusion Interfaces for Tactical Environments (FITE) Facility is a specialized flight simulator enabling efficient concept development through rapid prototyping and direct experience of new fusion concepts. The FITE Facility also supports evaluation of fusion concepts by operation fighter pilots in an air combat environment. The facility is utilized by a multidisciplinary design team composed of human factors engineers, electronics engineers, computer scientists, experimental psychologists, and oeprational pilots. The FITE computational architecture is composed of twenty-five 80486-based microcomputers operating in real-time. The microcomputers generate out-the-window visuals, in-cockpit and head-mounted visuals, localized auditory presentations, haptic displays on the stick and rudder pedals, as well as executing weapons models, aerodynamic models, and threat models.

Haas, Michael W.↗

Design oriented structural analysis

Desirable characteristics and benefits of design oriented analysis methods are described and illustrated by presenting a synoptic description of the development and uses of the Equivalent Laminated Plate Solution (ELAPS) computer code. ELAPS is a design oriented structural analysis method which is intended for use in the early design of aircraft wing structures. Model preparation is minimized by using a few large plate segments to model the wing box structure. Computational efficiency is achieved by using a limited number of global displacement functions that encompass all segments over the wing planform. Coupling with other codes is facilitated since the output quantities such as deflections and stresses are calculated as continuous functions over the plate segments. Various aspects of the ELAPS development are discussed including the analytical formulation, verification of results by comparison with finite element analysis results, coupling with other codes, and calculation of sensitivity derivatives. The effectiveness of ELAPS for multidisciplinary design application is illustrated by describing its use in design studies of high speed civil transport wing structures.

Giles, Gary L.↗

Runtime support for data parallel tasks

We have recently introduced a set of Fortran language extensions that allow for integrated support of task and data parallelism, and provide for shared data abstractions (SDA's) as a method for communications and synchronization among these tasks. In this paper we discuss the design and implementation issues of the runtime system necessary to support these extensions, and discuss the underlying requirements for such a system. To test the feasibility of this approach, we implement a prototype of the runtime system and use this to support an abstract multidisciplinary optimization (MDO) problem for aircraft design. We give initial results and discuss future plans.

Haines, Matthew↗

Turbulence modeling of free shear layers for high performance aircraft

In many flowfield computations, accuracy of the turbulence model employed is frequently a limiting factor in the overall accuracy of the computation. This is particularly true for complex flowfields such as those around full aircraft configurations. Free shear layers such as wakes, impinging jets (in V/STOL applications), and mixing layers over cavities are often part of these flowfields. Although flowfields have been computed for full aircraft, the memory and CPU requirements for these computations are often excessive. Additional computer power is required for multidisciplinary computations such as coupled fluid dynamics and conduction heat transfer analysis. Massively parallel computers show promise in alleviating this situation, and the purpose of this effort was to adapt and optimize CFD codes to these new machines. The objective of this research effort was to compute the flowfield and heat transfer for a two-dimensional jet impinging normally on a cool plate. The results of this research effort were summarized in an AIAA paper titled 'Parallel Implementation of the k-epsilon Turbulence Model'. Appendix A contains the full paper.

Sondak, Douglas↗

Modeling the Earth system in the Mission to Planet Earth era

A broad overview is made of global earth system modeling in the Mission to Planet Earth (MTPE) era for the multidisciplinary audience encompassed by the Global Change Research Program (GCRP). Time scales of global system fluctuation and change are described in Section 2. Section 3 provides a rubric for modeling the global earth system, as presently understood. The ability of models to predict the future state of the global earth system and the extent to which their predictions are reliable are covered in Sections 4 and 5. The 'engineering' use of global system models (and predictions) is covered in Section 6. Section 7 covers aspects of an increasing need for improved transform algorithms and better methods to assimilate this information into global models. Future monitoring and data requirements are detailed in Section 8. Section 9 covers the NASA-initiated concept 'Mission to Planet Earth,' which employs space and ground based measurement systems to provide the scientific basis for understanding global change. Section 10 concludes this review with general remarks concerning the state of global system modeling and observing technology and the need for future research.

Unninayar, Sushel↗

Design for an integrated discipline operations control center for Space Station Freedom

This paper presents selected features of a human factors oriented plan for a Space Station Freedom (SSF) ground Discipline Operations Center (DOC) that is integrated with other work areas used by multidisciplinary life scientists. This combined facility is referred to as an integrated DOC or IDOC. This plan is based upon the assumption that there will be a constantly changing array of specialized equipment and procedures used by life sciences principal investigators (PI) on the ground which must be linked to SSF through various DOC systems. Other sites will also be able to communicate with SSF (Anon., 1992). It is also assumed that cost reduction will be a major design consideration and that one integrated structure will be less expensive to build and operate than two separate ones. Since both the DOC personnel and PIs will need to communicate with the flight crew aboard SSF, the general interconnect architecture of the PIs' communication linkage is considered here. Key human factor design elements of this plan include: a candidate facility layout which accommodates three (3), multipurpose, rapidly reconfigurable work areas (suites) and consequent user traffic flow considerations, a multimedia telecommunications support capability, functional (human) traffic flow, optimized internal illumination and acoustics requirements, selected volumetric and safety requirements, and other architectural design parameters.

Haines, Richard F.↗

Global geologic applications of the Space Shuttle earth observations photography database

The advantages of the astronaut photography during Space Shuttle missions are briefly examined, and the scope and applications of the Space Shuttle earth observations photography database are discussed. The global and multidisciplinary nature of the data base is illustrated by several examples of geologic applications. These include the eruption of Mount Pinatubo (Philippine Islands), heat flow and ice cover on Lake Baikal in Siberia (Russia), and windblown dust in South America. It is noted that hand-held photography from the U.S. Space Shuttle provides unique remotely-sensed data for geologic applications because of the combination of varying perspectives, look angles, and illumination, and changing resolution resulting from different lenses and altitudes.

Lulla, Kamlesh↗

Multilevel algorithms for nonlinear optimization

Multidisciplinary design optimization (MDO) gives rise to nonlinear optimization problems characterized by a large number of constraints that naturally occur in blocks. We propose a class of multilevel optimization methods motivated by the structure and number of constraints and by the expense of the derivative computations for MDO. The algorithms are an extension to the nonlinear programming problem of the successful class of local Brown-Brent algorithms for nonlinear equations. Our extensions allow the user to partition constraints into arbitrary blocks to fit the application, and they separately process each block and the objective function, restricted to certain subspaces. The methods use trust regions as a globalization strategy, and they have been shown to be globally convergent under reasonable assumptions. The multilevel algorithms can be applied to all classes of MDO formulations. Multilevel algorithms for solving nonlinear systems of equations are a special case of the multilevel optimization methods. In this case, they can be viewed as a trust-region globalization of the Brown-Brent class.

Alexandrov, Natalia↗

State of the Data Union, 1992

This is the first report on the State of the Data Union (SDU) for the NASA Office of Space Science and Applications (OSSA). OSSA responsibilities include the collection, analysis, and permanent archival of data critical to space science research. The nature of how this is done by OSSA is evolving to keep pace with changes in space research. Current and planned missions have evolved to be more complex and multidisciplinary, and are generating much more data and lasting longer than earlier missions. New technologies enable global access to data, transfer of huge volumes of data, and increasingly complex analysis. The SDU provides a snapshot of this dynamic environment, identifying trends in capabilities and requirements. The current space science data environment is described and parameters which capture the pulse of key functions within that environment are presented. Continuous efforts of OSSA to improve the availability and quality of data provided to the scientific community are reported, highlighting efforts such as the Data Management Initiative.

Source record↗

Potential impacts of advanced aerodynamic technology on air transportation system productivity

Summaries of a workshop held at NASA Langley Research Center in 1993 to explore the application of advanced aerodynamics to airport productivity improvement are discussed. Sessions included discussions of terminal area productivity problems and advanced aerodynamic technologies for enhanced high lift and reduced noise, emissions, and wake vortex hazard with emphasis upon advanced aircraft configurations and multidisciplinary solution options.

Bushnell, Dennis M.↗

High speed civil transport aerodynamic optimization

This is a report of work in support of the Computational Aerosciences (CAS) element of the Federal HPCC program. Specifically, CFD and aerodynamic optimization are being performed on parallel computers. The long-range goal of this work is to facilitate teraflops-rate multidisciplinary optimization of aerospace vehicles. This year's work is targeted for application to the High Speed Civil Transport (HSCT), one of four CAS grand challenges identified in the HPCC FY 1995 Blue Book. This vehicle is to be a passenger aircraft, with the promise of cutting overseas flight time by more than half. To meet fuel economy, operational costs, environmental impact, noise production, and range requirements, improved design tools are required, and these tools must eventually integrate optimization, external aerodynamics, propulsion, structures, heat transfer, controls, and perhaps other disciplines. The fundamental goal of this project is to contribute to improved design tools for U.S. industry, and thus to the nation's economic competitiveness.

Ryan, James S.↗

Hypersonic Engine Leading Edge Experiments in a High Heat Flux, Supersonic Flow Environment

A major concern in advancing the state-of-the-art technologies for hypersonic vehicles is the development of an aeropropulsion system capable of withstanding the sustained high thermal loads expected during hypersonic flight. Three aerothermal load related concerns are the boundary layer transition from laminar to turbulent flow, articulating panel seals in high temperature environments, and strut (or cowl) leading edges with shock-on-shock interactions. A multidisciplinary approach is required to address these technical concerns. A hydrogen/oxygen rocket engine heat source has been developed at the NASA Lewis Research Center as one element in a series of facilities at national laboratories designed to experimentally evaluate the heat transfer and structural response of the strut (or cowl) leading edge. A recent experimental program conducted in this facility is discussed and related to cooling technology capability. The specific objective of the experiment discussed is to evaluate the erosion and oxidation characteristics of a coating on a cowl leading edge (or strut leading edge) in a supersonic, high heat flux environment. Heat transfer analyses of a similar leading edge concept cooled with gaseous hydrogen is included to demonstrate the complexity of the problem resulting from plastic deformation of the structures. Macro-photographic data from a coated leading edge model show progressive degradation over several thermal cycles at aerothermal conditions representative of high Mach number flight.

Gladden, Herbert J.↗