Von Neumann Stability Analysis of DG-Like and PNPM-Like Schemes for PDEs with Globally Curl-Preserving Evolution of Vector Fields
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Dinshaw S. Balsara↗
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Results for “stability analysis”
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Three-dimensional nonlinear stability analysis of the sun-perturbed Earth-Moon equilateral points
Nonlinear analytic study of long period features of particle motion in Earth-Moon system
EARTH-MOON SYSTEM↗
Nonlinear stability analysis of Apollo aft heat shield
Nonlinear structural analysis of stress and buckling pressures of aft heat shield of Apollo spacecraft
Stricklin, J. A.↗
Stability analysis of Apollo-Saturn V propulsion and structure feedback loop.
Apollo-Saturn 5 propulsion and structure feedback loop, analyzing Pogo components and Nyquist plot application
Von Pragenau, G. L.↗
Further development of an algorithm for the nonlinear stability analysis of the orbiting astronomical observatory paired-tracker control system Final report
Algorithm development for estimating domain of attraction of OAO paired-tracker equilibrium state with Liapunov functions
Chomas, A.↗
A stability analysis for a semilinear parabolic partial differential equation
The parabolic partial differential equation considered is u sub t = u sub xx + f(u), where minus infinity x plus infinity and o t plus infinity. Under suitable hypotheses pertaining to f, a class of initial data is exhibited: phi(x), minus infinity x plus infinity, for which the corresponding solutions u(x,t) appraoch zero as t approaches the limit of plus infinity. This convergence is uniform with respect to x on any compact subinterval of the real axis.
Chafee, N.↗
The finite element method in shell stability analysis.
A development of the finite element method for thin shell instability analysis is presented, covering three principal aspects: (1) representation of shell geometry, (2) representation of element behavior, and (3) algorithmic tools for solution of the large-order systems of nonlinear algebraic equations which characterize various phases of shell instability. Two shell elements are described, an arbitrary quadrilateral and a triangle, and numerical results are presented for two widely-employed comparison problems for linear (stable) analysis. Two shell problems which include instability effects are also solved.-
Gallagher, R. H.↗
Research study on stabilization and control. Modern sampled-date control theory. Stability analysis of the low cost large space telescope system
A mathematical model employing Fourier series is used to show quantization and reaction wheel friction nonlinearity in a telescope system for use in space. Block diagrams are used to illustrate the system. A discrete describing function of a quantizer also is given, and input and output signal waveforms, with illustrative examples, are shown.
Kuo, B. C.↗
Stability analysis of nonlinear autonomous systems - General theory and application to flutter
The analysis makes use of a singular perturbation method, the multiple time scaling. Concepts of stable and unstable limit cycles are introduced. The solution is obtained in the form of an asymptotic expansion. Numerical results are presented for the nonlinear flutter of panels and airfoils in supersonic flow. The approach used is an extension of a method for analyzing nonlinear panel flutter reported by Morino (1969).
Smith, L. L.↗
Computer program system for dynamic simulation and stability analysis of passive and actively controlled spacecraft. Volume 2: Program user's guide
For abstract, see N76-25319.
Bodley, C. S.↗
Computer program system for dynamic simulation and stability analysis of passive and actively controlled spacecraft. Volume 3: Demonstration problems
For abstract, see N76-25319.
Bodley, C. S.↗
Stability analysis of a liquid fuel annular combustion chamber
The problems of combustion instability in an annular combustion chamber are investigated. A modified Galerkin method was used to produce a set of modal amplitude equations from the general nonlinear partial differential acoustic wave equation. From these modal amplitude equations, the two variable perturbation method was used to develop a set of approximate equations of a given order of magnitude. These equations were modeled to show the effects of velocity sensitive combustion instabilities by evaluating the effects of certain parameters in the given set of equations. By evaluating these effects, parameters which cause instabilities to occur in the combustion chamber can be ascertained. It is assumed that in the annular combustion chamber, the liquid propellants are injected uniformly across the injector face, the combustion processes are distributed throughout the combustion chamber, and that no time delay occurs in the combustion processes.
Mcdonald, G. H.↗
Stability analysis of a liquid fuel annular combustion chamber
High frequency combustion instability problems in a liquid fuel annular combustion chamber are examined. A modified Galerkin method was used to produce a set of modal amplitude equations from the general nonlinear partial differential acoustic wave equation in order to analyze the problem of instability. From these modal amplitude equations, the two variable perturbation method was used to develop a set of approximate equations of a given order of magnitude. These equations were modeled to show the effects of velocity sensitive combustion instabilities by evaluating the effects of certain parameters in the given set of equations.
Mcdonald, G. H.↗
Flexible body stability analysis of Space Shuttle ascent flight control system by using lambda matrix solution techniques
A lambda matrix solution technique is being developed to perform an open loop frequency analysis of a high order dynamic system. The procedure evaluates the right and left latent vectors corresponding to the respective latent roots. The latent vectors are used to evaluate the partial fraction expansion formulation required to compute the flexible body open loop feedback gains for the Space Shuttle Digital Ascent Flight Control System. The algorithm is in the final stages of development and will be used to insure that the feedback gains meet the design specification.
Bown, R. L.↗
Aerodynamic stability analysis of NASA J85-13/planar pressure pulse generator installation
A digital computer simulation model for the J85-13/Planar Pressure Pulse Generator (P3 G) test installation was developed by modifying an existing General Electric compression system model. This modification included the incorporation of a novel method for describing the unsteady blade lift force. This approach significantly enhanced the capability of the model to handle unsteady flows. In addition, the frequency response characteristics of the J85-13/P3G test installation were analyzed in support of selecting instrumentation locations to avoid standing wave nodes within the test apparatus and thus, low signal levels. The feasibility of employing explicit analytical expression for surge prediction was also studied.
Chung, K.↗
An investigation of the origin of the flow turning effect in combustion stability analysis
The concept of a "flow turning" effect in the combustion based on the fact that terms appear in the equations governing the acoustic oscillations in a one dimensional model of combustion in a solid propellant rocket that do not appear in a three dimensional model. A procedure is developed to allow comparison of one and three dimensional models by averaging over the cross section of the motor cavity. Results indicate that the one dimensional equations with mass addition do not contain any physical phenomena that are missing the three dimensional equations with appropriate boundary conditions. This raises significant questions about any procedure that is based on the difference between one and three dimensional results.
Vanmoorhem, W. K.↗
Large displacements and stability analysis of nonlinear propeller structures
The use of linear rigid formats in COSMIC NASTRAN without DMAP procedures for the analysis of nonlinear propeller structures is described. Approaches for updating geometry and applying follower forces for incremental loading are demonstrated. Comparisons are made with COSMIC NASTRAN rigid formats and other independent finite element programs. Specifically, the comparisons include results from the four approaches for updating the geometry using RIGID FORMAT 1, RIGID FORMATS 4 and 13, MARC and MSC/NASTRAN. It is shown that 'user friendly' updating approaches (without DMAPS) can be used to predict the large displacements and instability of these nonlinear structures. These user friendly approaches can be easily implemented by the user and predict conservative results.
Aiello, R. A.↗
Large displacements and stability analysis of nonlinear propeller structures
The use of linear rigid formats in COSMIC NASTRAN without DMAP procedures for the analysis of nonlinear propeller structures is described. Approaches for updating geometry and applying follower forces for incremental loading are demonstrated. The COSMIC NASTRAN rigid formats and other independent finite element programs are compared. The comparisons include results from the four approaches for updating the geometry using RIGID FORMAT 1, RIGID FORMATS 4 and 13, MARC and MSC/NASTRAN. It is shown that user friendly updating approaches can be used to predict the large displacements and instability of these nonlinear structures. The approaches are easily implemented by the user and predict conservative results.
Aiello, R. A.↗