Scientific and Technical Aerospace Reports Volume 38 July 28, 2000

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The authors discuss the parallelization of an implicit solver for the 2d Euler equations on a structured grid. The spatial distribution involves the MUSCL scheme, a Total Variation Diminishing scheme. It is shown that an implicit solver that is based on quasi- Newton iteration and approximate factorization to solve the linear system of equations resulting from the Euler Backward scheme, has favorable properties for both multigrid acceleration and parallelization as compared to explicit Runge-Kutta time stepping. to preserve data locality, the authors apply domain decomposition to obtain a parallelizable code. Although the domain decomposition does affect the efficiency of the approximately factorization method, the results show that this hardly affects the convergence rate as obtained with a single block code. the accuracy with which the linear system of equations is solved is found to be an important parameter. The combination of parallel execution and implicit time integration provides an interesting perspective for time dependent problems in computational fluid dynamics. NTIS Algorithms; Inviscid Flow; Computational Fluid Dynamics 20000064608 NASA Ames Research Center, Moffett Field, CA USA NASA’s Aero-Space Technology Milstead, Phil, NASA Ames Research Center, USA; February 2000; In English; See also 20000064579; No Copyright; Abstract Only; Available from CASI only as part of the entire parent document This presentation reviews the three pillars and the associated goals of NASA’s Aero-Space Technology Enterprise. The three pillars for success are: (1) Global Civil Aviation, (2) Revolutionary Technology Leaps, (3) Advanced Space Transportation. The associated goals of the first pillar are to reduce accidents, emissions, and cost, and to increase the aviation system capacity. The goals of the second pillar are to reduce transoceanic travel time, revolutionize general aviation aircraft, and improve development capacity. The goals associated with the third pillar are to reduce the launch cost for low earth orbit and to reduce travel time for planetary missions. In order to meet these goals NASA must provide next-generation design capability for new and or experimental craft which enable a balance between reducing components of the design cycle by up to 50% and or increasing the confidence in design by 50%. These next-generation design tools, concepts, and processes will revolutionize vehicle development. The presentation finally reviews the importance of modeling and simulation in achieving the goals. CASI Simulation; Models; NASA Programs; Space Programs; Technology Utilization 20000064627 Boeing Co., Phantom Works, Long Beach, CA USA Viscous Design Optimization Using ADJIFOR - An HPCCP Perspective Sundaram, P., Boeing Co., USA; Agrawal, Shreekant, Boeing Co., USA; Hager, James O., Boeing Co., USA; Carle, Alan, Rice Univ., USA; Fagan, Mike, Rice Univ., USA; February 2000; In English; See also 20000064579; No Copyright; Abstract Only; Available from CASI only as part of the entire parent document The accurate computation of objective function sensitivity to design variable (DV) perturbations is the most crucial and expensive element of gradient-based optimization. In a nonlinear aerodynamic optimization problem, where the objective functions are computed based on Euler/Navier-Stokes codes, the computation of sensitivities becomes a computational challenge even for today’s large parallel systems. The situation gets even worse in constrained aerodynamic shape optimizations where the number of DVs tend to be rather large. The finite-difference method of calculating gradients for these problems is ruled out for two reasons: prohibitive cost and approximation error. Adjoint methods are essential for calculating the gradients. Primary among the adjoint methods is the method of deriving the adjoints by posing the original continuous form of the problem as a calculus of variations problem. This method requires long and tedious analytical derivations and hand-differentiation of the underlying partial differential equations. Furthermore, turbulence models present in Navier-Stokes equation solvers complicate the construction of adjoint codes. Consequently, few commercial Navier-Stokes adjoint codes are available, and those that are available cannot be easily adapted for use in the desired design environment. Automatic differentiation (AD) using ADIFOR has been known for sometime to be an accurate method of calculating analytical sensitivities of a FORTRAN function code. The forward-mode ADI- FOR and adjoint-mode ADJIFOR tools (both components of the soon to be released ADIFOR 3.0 System) automatically enhance function codes with code to compute the required derivatives. In the past year, sensitivity calculations performed by ADIFOR and ADJIFOR-differentiated codes have shown great promise. In last year’s HPCCP/CAS workshop, we presented initial results using an ADJIFOR-differentiated version of the CFL3D/Euler code on a shape design optimization problem. The present paper provides further details on the use of the derivative-enhanced CFL3D code as the basis of an automated design environment. In addition, the paper presents a successful HSCT configuration design discovered using this environment on the NAS Origin 2000 parallel system. This success on the CFL3D/Euler code has led to the application of ADJIFOR to compute flow sensitivities for the CFL3D/Navier-Stokes code. The paper compares gradient accuracy and time requirements for computing Navier-Stokes flow sensitivities using both ADIFOR and ADJIFOR-differentiated codes and describes additional steps taken to improve the effi- 6
ciency of the generated derivative code. Finally, the paper describes the trials and tribulations of adapting ADJIFOR-processed CFL3D viscous gradients for the aerodynamic shape optimization-based design environment to the NAS Origin 2000 and applying it to HSCT configuration design problem. Author Applications Programs (Computers); Computational Fluid Dynamics; Design Analysis; Navier-Stokes Equation; Optimization; Computer Systems Design; Computerized Simulation; Mathematical Models 20000064715 Mississippi State Univ., Dept. of Aerospace Engineering, Mississippi State, MS USA Aero-Structural Interaction, Analysis, and Shape Sensitivity, 1 Jan. - 31 Dec. 1999 Newman, James C., III, Mississippi State Univ., USA; [1999]; 11p; In English Contract(s)/Grant(s): NCC1-286 Report No.(s): AIAA Paper 99-3101; No Copyright; Avail: CASI; A03, Hardcopy; A01, Microfiche A multidisciplinary sensitivity analysis technique that has been shown to be independent of step-size selection is examined further. The accuracy of this step-size independent technique, which uses complex variables for determining sensitivity derivatives, has been previously established. The primary focus of this work is to validate the aero-structural analysis procedure currently being used. This validation consists of comparing computed and experimental data obtained for an Aeroelastic Research Wing (ARW-2). Since the aero-structural analysis procedure has the complex variable modifications already included into the software, sensitivity derivatives can automatically be computed. Other than for design purposes, sensitivity derivatives can be used for predicting the solution at nearby conditions. The use of sensitivity derivatives for predicting the aero-structural characteristics of this configuration is demonstrated. Author Aeroelasticity; Structural Analysis; Sensitivity; Structural Design; Design Analysis; Shapes 20000067656 NASA Langley Research Center, Hampton, VA USA Exploratory Investigation of Aerodynamic Characteristics of Helicopter Tail Boom Cross-Section Models with Passive Venting Banks, Daniel W., NASA Dryden Flight Research Center, USA; Kelley, Henry L., Army Aviation and Missile Command, USA; June 2000; 52p; In English Contract(s)/Grant(s): RTOP 10-11-01 Report No.(s): NASA/TP-2000-210083; NAS 1.60:210083; AMCOM-AFDD/TR-00-A-007; L-17770; No Copyright; Avail: CASI; A04, Hardcopy; A01, Microfiche Two large-scale, two-dimensional helicopter tail boom models were used to determine the effects of passive venting on boom down loads and side forces in hovering crosswind conditions. The models were oval shaped and trapezoidal shaped. Completely porous and solid configurations, partial venting in various symmetric and asymmetric configurations, and strakes were tested. Calculations were made to evaluate the trends of venting and strakes on power required when applied to a UH-60 class helicopter. Compared with the UH-60 baseline, passive venting reduced side force but increased down load at flow conditions representing right sideward flight. Selective asymmetric venting resulted in side force benefits close to the fully porous case. Calculated trends on the effects of venting on power required indicated that the high asymmetric oval configuration was the most effective venting configuration for side force reduction, and the high asymmetric with a single strake was the most effective for overall power reduction. Also, curves of side force versus flow angle were noticeable smoother for the vented configurations compared with the solid baseline configuration; this indicated a potential for smoother flight in low-speed crosswind conditions. Author Aerodynamic Characteristics; Helicopters; Strakes; Aerodynamic Configurations; Two Dimensional Models; Tail Assemblies 7
Page 1 and 2: Scientific and Technical Aerospace
Page 3 and 4: Introduction Scientific and Technic
Page 5 and 6: Subject Divisions Table of Contents
Page 7 and 8: ground equipment and systems. For a
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Page 11 and 12: 48 Oceanography 139 Includes the ph
Page 13 and 14: 72 Atomic and Molecular Physics 191
Page 15 and 16: Document Availability Information T
Page 17 and 18: Avail: NASA Public Document Rooms.
Page 19 and 20: NASA CASI Price Tables — Effectiv
Page 21 and 22: ALABAMA AUBURN UNIV. AT MONTGOMERY
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Page 25 and 26: 20000061433 Pisa Univ., Dipartiment
Page 27: English; 34th; 34th Thermophysics C
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Page 33 and 34: 05 AIRCRAFT DESIGN, TESTING AND PER
Page 35 and 36: A long tradition of aerodynamic des
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Page 43 and 44: performance required for a proposed
Page 45 and 46: ment cost and create better product
Page 47 and 48: tion (NPSS), is focused on the inte
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Page 51 and 52: with emphasis on the search for lin
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Page 55 and 56: primary issues for it’s adaptatio
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Page 61 and 62: necessary for ignition modeling, or
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Page 67 and 68: ments. For the screening of liner m
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Page 73 and 74: This is a second Triennial Conferen
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Spacecraft in low Earth orbit (LEO)
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Pressure gradients, i.e. pressure h
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agreed that the NO(sub x) levels co
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tectural approach to extending the
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20000064078 Physics and Electronics
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20000064925 Institute for Human Fac
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20000062455 National Inst. of Stand
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Added Analysis (Risk Reduction); 6)
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shipboard electrical power generati
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20000067664 Jet Propulsion Lab., Ca
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other, The theoretical framework go
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figures compare the lift and pitchi
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ment phase demonstrate desired feat
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esolution mode with resolving power
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to track 1% or 0.5% changes was hig
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20000067643 NASA Marshall Space Fli
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37 MECHANICAL ENGINEERING ��
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solver based on overset grid techno
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20000064621 Rensselaer Polytechnic
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that for a specific example of a be
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km x 1000 km). As with the nearly c
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20000064527 Analytical Imaging and
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20000064533 Austin State Univ., Dep
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20000064539 California Univ., Inst.
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in Yellowstone National Park. We ar
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terns of community hysteresis based
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tion model (DEM) fitting to the sca
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The Carolina slate belt is a 10- to
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20000063373 Los Alamos National Lab
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20000064912 New Energy and Industri
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and discusses the issues and resear
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The objective of this study was to
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distributions with engine test resu
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7.6, while the 1926 events appear t
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We investigate the compositional di
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Flight Center, USA; Moore, T. E., N
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This report presents the Applied Me
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in Goa, India, by 3 - 4 days. Wind
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51 LIFE SCIENCES (GENERAL) Includes
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20000062717 Joint Inst. for Nuclear
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during 50% (SD 4%) of the breathing
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20000064711 Massachusetts Inst. of
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The analysis of this smaller data s
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vided a functional helmet mount. Th
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61 COMPUTER PROGRAMMING AND SOFTWAR
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The goal of multi-image classificat
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20000063526 Defence Science and Tec
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85 dB amplifier design evolved by o
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20000064594 New Mexico Univ., Elect
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20000064615 NASA Ames Research Cent
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declarations with a pattern recogni
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containing point where interpolatio
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has his own responsibility, while t
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the people, documents and projects
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and experimental technology, many o
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tems. In particular this applicatio
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Over the past decade, high performa
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expensive than a single analysis. I
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20000064726 Carnegie-Mellon Univ.,
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20000064099 Teledyne Brown Engineer
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20000066597 Geophysical Observatory
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20000065633 Institute TNO of Applie
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important conclusion is that for su
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est frame of the string. The modifi
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isotopes. The method and program we
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A detailed study is undertaken, usi
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20000063497 Kaiser Electro-Optics,
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delivers 60% of the x-ray flux from
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76 SOLID-STATE PHYSICS ��
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20000064660 Abdus Salam Internation
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20000064703 Institute of Atomic Ene
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The BRST approach is applied to the
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20000067671 Hampton Univ., VA USA A
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82 DOCUMENTATION AND INFORMATION SC
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ecoming almost too cumbersome to be
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physical world. These are the two p
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with WFPC2 data. Tests of HSTphot
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A brief description is given of the
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20000064070 NASA Ames Research Cent
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gas, show variations that have rema
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egy, called Power In that would all
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20000065631 NASA Kennedy Space Cent
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20000064089 Smithsonian Astrophysic
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A ABERRATION, 143, 198 ABRASION, 22
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COMPRESSIBLE FLOW, 83 COMPRESSION L
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FATIGUE (MATERIALS), 50, 93, 96 FAT
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LASING, 90 LATE STARS, 224 LATITUDE
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PATCH ANTENNAS, 74 PATHOLOGY, 98 PA
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SPACE PLATFORMS, 38 SPACE PROBES, 2
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WIND PROFILES, 137 WIND TUNNEL TEST
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Brown, Andy, 38 Brown, April S., 20
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Grosvenor, C. A., 70 Grosvenor, J.
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Lu, Gui-Ying, 50 Lugg, Desmond J.,
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Robertson, Tony, 39 Robinson, Jeffr
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Warner, J. D., 63 Warren, James, 16
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Scientific and Technical Aerospace Reports Volume 38 July 28, 2000

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