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FULL-WAVE SOLUTION OF DIELECTRIC LOADED WAVE-GUIDES AND SHIELDED MICROSTRIPS UTILIZING FINITE-DIFFERENCE AND THE CONJUGATE-GRADIENT METHOD

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INTERNATIONAL JOURNAL OF MICROWAVE AND MILLIMETER-WAVE computer-AIDED engineering 1991年第4期1卷 346-357页

作者： NARAYANAN, V MANELA, M LADE, RK SARKAR, TK Department of Electrical and Computer Engineering Syracuse University Syracuse New York 13244-1240 Viswanathan Narayanan was born in Bangalore India on December 14 1965. He received the BE degree in Electronics and Communications from B.M.S. College of Engineering Bangalore in 1988. He joined the Department of Electrical Engineering at Syracuse University for his graduate studies in 1989 where he is currently a research assistant. His research interests are in microwave measurements numerical electromagnetics and signal processing. Biographies and photos are not available for M. Manela and R. K. Lade. Tapan K. Sarkar (Sf69-M'76-SM'X1) was born in Calcutta. India on August 2 1948. He received the BTech degree from the Indian Institute of Technology Kharagpur India in 1969 the MScE degree from the University of New Brunswick Fredericton Canada in 1971. and the MS and PhD degrees from Syracuse University. Syracuse NY in 1975. From 1975-1976 he was with the TACO Division of the General Instruments Corporation. He was with the Rochester Institute of Technology (Rochester NY) from 1976-1985. He was a Research Fellow at the Gordon Mckay Laboratory Harvard University Cambridge MA from 1977 to 1978. He is now a Professor in the Department of Electrical and Computer Engineering Syracuse University. His current research interests deal with numerical solutions of operator equations arising in electromagnetics and signal processing with application to system design. He obtained one of the “ best solution” awards in May 1977 at the Rome Air Development Center (RADC) Spectral Estimation Workshop. He has authored or coauthored more than 154 journal articles and conference papers and has written chapters in eight books. Dr. Sarkar is a registered professional engineer in the state of New York. He received the Best Paper Award of the IEEE Transactions on Electromagnetic Compatibility in 1979. He was an Associate Editor for feature articles of the lEEE Antennas arid Propagation Sociefy Newsletter and was

Dynamic analysis of waveguide structures containing dielectric and metal strips is presented. The analysis utilizes a finite difference frequency domain procedure to reduce the problem to a symmetric matrix eigenvalue problem. Since the matrix is also sparse, the eigenvalue problem can be solved quickly and efficiently using the conjugate gradient method resulting in considerable savings in computer storage and time. Comparison is made with the analytical solution for the loaded dielectric waveguide case. For the microstrip case, we get both waveguide modes and quasi-TEM modes. The quasi-TEM modes in the limit of zero frequency are checked with the static analysis which also uses finite difference. Some of the quasi-TEM modes are spurious. This article describes their origin and discusses how to eliminate them. Numerical results are presented to illustrate the principles.

关键词： Waveguides

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A NONLINEAR INVESTIGATION OF THE STATIONARY MODES OF INSTABILITY OF THE 3-DIMENSIONAL COMPRESSIBLE BOUNDARY-LAYER DUE TO A ROTATING-DISK

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QUARTERLY JOURNAL OF MECHANICS AND APPLIED MATHEMATICS 1990年第4期43卷 467-497页

作者： SEDDOUGUI, SO Institute of Computer Applications in Science and Engineering NASA Langley Research CenterHampton Virginia 23665 USA

This work investigates the effects of compressibility on a stationary mode of instability of the three-dimensional boundary layer due to a rotating disc. The aim is to determine whether this mode will be important in the finite-amplitude destabilization of the boundary layer. This stationary mode is characterized by the effective velocity profile having zero shear stress at the wall. Triple-deck solutions are presented for an adiabatic wall and an isothermal wall. It is found that this stationary mode is only possible over a finite range of Mach numbers. Asymptotic solutions are obtained which describe the structure of the wave number and the orientation of these modes as functions of the local Mach number. The effects of nonlinearity are investigated allowing the finite-amplitude growth of a disturbance close to the neutral location to be described. The results are compared with the incompressible results of Hall (1) and MacKerrell (2).

关键词： Flow of Fluids

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ADAPTIVE MESH GENERATION FOR VISCOUS FLOWS USING DELAUNAY TRIANGULATION

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JOURNAL OF COMPUTATIONAL PHYSICS 1990年第2期90卷 271-291页

作者： MAVRIPLIS, DJ Institute for Computer Applications in Science and Engineering NASA Langley Research Center Hampton Virginia 23665 USA

A method for generating an unstructured triangular mesh in two dimensions, suitable for computing high Reynolds number flows over arbitrary configurations is presented. The method is based on a Delaunay triangulation, which is perfored in a locally stretched space, in order to obtain very high-aspect-ratio tiangles in the boundary layer and wake regions. It is shown how the method can be coupled with an unstructured Navier-Stokes solver to produce a solution-adaptive mesh generation procedure for viscous flows.

关键词： Viscous flow

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A SIMPLE NONLINEAR MODEL FOR THE RETURN TO ISOTROPY IN TURBULENCE

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PHYSICS OF FLUIDS A-FLUID DYNAMICS 1990年第1期2卷 84-93页

作者： SARKAR, S SPEZIALE, CG Institute for Computer Applications in Science and Engineering NASA Langley Research Center Hampton Virginia 23665

A quadratic nonlinear generalization of the linear Rotta model for the slow pressure‐strain correlation of turbulence is developed for high Reynolds number flows. The model is shown to satisfy realizability and to give rise to no stable nonzero equilibrium solutions for the anisotropy tensor in the case of vanishing mean velocity gradients. In order for any model to predict a return to isotropy for all relaxational flows, it is necessary to ensure that there is no nonzero stable fixed point that attracts realizable initial conditions. Both the phase space dynamics and the temporal behavior of the model are examined and compared against experimental data for the return to isotropy problem. It is demonstrated that the quadratic model successfully captures the experimental trends which clearly exhibit nonlinear behavior. Comparisons are also made with the predictions of the linear Rotta model, the quasilinear Lumley model, and the nonlinear model of Shih, Mansour, and Moin. The simple quadratic model proposed in this study does better than the Rotta model as anticipated, and also compares quite favorably with the other more complicated nonlinear models.

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The analysis and simulation of compressible turbulence

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Theoretical and Computational Fluid Dynamics 1990年第2期2卷 73-95页

作者： Erlebacher, Gordon Hussaini, M.Y. Kreiss, H.O. Sarkar, S. Institute for Computer Applications in Science and Engineering NASA Langley Research Center Hampton 23665 VA United States University of California at Los Angeles Los Angeles 90024 CA United States Institute for Computer Applications in Science and Engineering NASA Langley Research Center Hampton 23665 VA United States

This paper considers compressible turbulent flows at low turbulent Mach numbers. Contrary to the general belief that such flows are almost incompressible (i.e., the divergence of the velocity field remains small for all times), it is shown that even if the divergence of the initial velocity field is negligibly small, it can grow rapidly on a nondimensional time scale which is the order of the fluctuating Mach number. An asymptotic theory which enables a description of the flow in terms of its divergence-free and vorticity-free components has been developed to solve the initial-value problem. As a result, the various types of low Mach number turbulent regimes have been classified with respect to the initial conditions. Formulae are derived that accurately predict the level of compressibility after the initial transients have disappeared. These results are verified by extensive direct numerical simulations of isotropic turbulence. © 1990 Springer-Verlag.

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AN ANNEALING-BASED CIRCUIT PARTITIONER FOR HYPERCUBE ARCHITECTURE: DESIGN AND PERFORMANCE EVALUATION

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International Journal of High Speed Computing 1990年第1期2卷 69-84页

作者： SRILATA RAMAN L.M. PATNAIK Dept. of Electrical and Computer Engineering and Coordinated Science Laboratory University of Illinois at Urbana-Champaign IL 61801 U.S.A Microprocessor Applications Laboratory Dept. of Computer Science and Automation and Supercomputer Education and Research Center Indian Institute of Science Bangalore 560 012 India

This paper discusses the parallel implementation of a hypercube-based circuit partitioning scheme. The circuit partitioner is based on a simulated annealing algorithm and is designed to provide near optimal circuit partitions for simulating the circuits on a hypercube architecture. The circuit partitioning scheme optimizes multiple criteria such as tight coupling of nodes within a subcircuit, load balancing among processors and communication overheads. Design of a partitioner that obtains near optimal solutions satisfying such multiple criteria is difficult using any simple heuristic techniques other than simulated annealing.

关键词： Circuit simulation circuit partitioning simulated annealing hypercube architecture

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PARALLEL IMPLEMENTATION OF CIRCUIT SIMULATION

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International Journal of High Speed Computing 1990年第4期2卷 351-373页

作者： SRILATA RAMAN L.M. PATNAIK R. MALL Dept. of Electrical and Computer Engineering and Coordinated Science Laboratory University of Illinois at Urbana-Champaign IL 61801 U.S.A Microprocessor Applications Laboratory Indian Institute of Science Bangalore 560 012 India Supercomputer Education and Research Centre Indian Institute of Science Bangalore 560 012 India Dept. of Computer Science and Automation Indian Institute of Science Bangalore 560 012 India

The importance of circuit simulation in the design of VLSI circuits has channelised research work in the direction of finding methods to speedup this highly compute-intensive problem. On one hand, attempts have been made to find better algorithms and use faster hardware; and on the other hand, to use parallel architectures for accelerating the circuit simulation task. In this paper, we examine the various issues involved in parallelizing two well-known circuit simulation approaches – direct methods and relaxation methods. A number of parallel computer architectures which have been used for this purpose are also surveyed.

关键词： Circuit simulation VLSI circuit design direct method relaxation method parallel processing

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computer-AIDED-DESIGN METHODS FOR PROPELLER FILLET GAUGES

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NAVAL ENGINEERS JOURNAL 1990年第3期102卷 202-208页

作者： ALLEN, DW VINOSKI, WS OVERTON, BA David W. Allen:is a senior computer scientist at the Machinery Technology Division Westinghouse Electric Corporation Large Pa. He received the B.A. degree in mathematics from Grinnell College and the M.S. degree in computer science from the University of Pittsburgh. His career with Westinghouse has been divided between assignments in engineering and computer applications. Mr. Allen has published eight technical papers. He received the George Westinghouse Signature A ward of Excellence for his work on the development of the GAGES computer program for designing propeller gages. He is a member of the Association for Computing Machinery (ACM) and the Institute of Electrical and Electronics Engineers (IEEE). Walter S. Vinoski:is a project engineer at the Machinery Technology Division Westinghouse Electric Corporation Large Pa. and was instrumental in the development of the GAGES computer program. He was awarded the George Westinghouse Signature Award of Excellence for his work on the GAGES program. Mr. Vinoski has six years of marine propulsion system experience specifically with propellers. He earned a B.S. degree in electronics engineering and minored in mathematics at the Ohio Institute of Technology. He is a member of the American Society of Naval Engineers. Bernard A. Overton:graduated from North Carolina Agricultural and Technical State University Greensboro N.C. in 1958 with a B.S. degree in mechanical engineering. Within two years of joining the U.S. Army Mr. Overton was honorably discharged as a first lieutenant. Mr. Overton worked seven years at Philadelphia Naval Shipyard in the following areas: shafting shafting alignment bearing reactions noise and vibration surveys propellers and propeller blade gage designs. In 1967 Mr. Overton transferred to the Navy Engineering Center. He has worked on main propulsion devices such as water jets propellers (both submarine and surface ship) and propeller blade gages. Mr. Overton was responsible for the establishment of the Naval Inspectors Propeller Certif

One of the most complicated forms encountered in engineering design is that of the marine propeller. The complexities arise from the complicated hydrodynamic surfaces of the propeller blades and the complicated manner in which the blades are oriented with and attached to the hub. Where propeller blades are attached to the hub, the blade shape is blended into the shape of the hub. The geometry of this region is particularly complicated. The shape of the blend is called a fillet, and the blending region is called the fillet region. Sheet metal gages conforming to various blade surface contours are used in the manufacture and inspection of propellers. Five different types of gages define the shape of the propeller in different regions. Fillet gages are such gages that define the shape of propeller blades in the fillet region. This paper describes a new computer-aided method for designing fillet gages. Previous methods of fillet gage design required the designer to follow a complicated layout procedure of determining where a particular unfilleted blade contour intersected the hub. The design of the fillet was then done in another layout procedure. Newly developed numerical procedures incorporated in a computer program have reduced the time required to design a complete set of gages (including fillet gages) from up to several weeks to hours.

关键词： Propellers

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FILE CONCEPTS FOR PARALLEL I/O 89

FILE CONCEPTS FOR PARALLEL I/O

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CONF ON SUPERCOMPUTING ( SUPERCOMPUTING 89 )

作者： CROCKETT, TW Institute for Computer Applications in Science and Engineering

ISBN: (纸本)0897913418

The subject of I/O has often been neglected in the design of parallel computer systems, although for many problems I/O rates will limit the speedup attainable. The I/O problem is addressed here by considering the role of files in parallel systems. The notion of parallel files is introduced. Parallel files provide for concurrent access by multiple processes, and utilize parallelism in the I/O system to improve performance. Parallel files can also be used conventionally by sequential programs. A set of standard parallel file organizations is proposed, based on common data partitioning techniques. Implementation strategies for the proposed organizations are suggested, using multiple storage devices. Problem areas are also identified and discussed.

关键词： computer systems programming

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SCALING LAWS FOR HOMOGENEOUS TURBULENT SHEAR FLOWS IN A ROTATING FRAME

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PHYSICS OF FLUIDS A-FLUID DYNAMICS 1989年第2期1卷 294-301页

作者： SPEZIALE, CG MHUIRIS, NM Institute for Computer Applications in Science and Engineering NASA Langley Research Center Hampton Virginia 23665

The scaling properties of plane homogeneous turbulent shear flows in a rotating frame are examined mathematically by a direct analysis of the Navier–Stokes equations. It is proved that two such shear flows are dynamically similar if and only if their initial dimensionless energy spectrum E*(k*,0), initial dimensionless shear rate SK0/ε0, initial Reynolds number K20/νε0, and the ratio of the rotation rate to the shear rate Ω/S are identical. Consequently, if universal equilibrium states exist at high Reynolds numbers, they will only depend on the single parameter Ω/S. The commonly assumed dependence of such equilibrium states on Ω/S through the Richardson number Ri=−2(Ω/S)(1−2Ω/S) is proved to be inconsistent with the full Navier–Stokes equations and to constitute no more than a weak approximation. To be more specific, Richardson number similarity is shown to only rigorously apply to certain low‐order truncations of the Navier–Stokes equations (i.e., to certain second‐order closure models) wherein closure is achieved at the second‐moment level by assuming that the higher‐order moments are a small perturbation of their isotropic states. The physical dependence of rotating turbulent shear flows on Ω/S is discussed in detail, along with the implications for turbulence modeling.

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