Engineer dynamics and productivity in r and d projects organizational research program
Engineer acquisition and utilization in research and development projects
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Engineer acquisition and utilization in research and development projects
Fluid amplifier dynamic characteristics and Fortran program for numerical solution of time- dependent two-dimensional Navier-Stokes equation for viscous jet in arbitrary flow field
Irradiation system for experiments with Plum Brook Reactor in nuclear rocket program, noting cryogenic system, dynamic testing, etc
Effects of flexible body aerodynamics on launch vehicles
Spacecraft antenna optimization, receptance coupling program, deformation modes and dynamic response of structures, and holographic measurements
Dynamic formalism and computer program for multiple space vehicle attitude and control simulations
An experimental program to determine the power-on aerodynamic flight characteristics of the booster and orbiter vehicles during the abort separation maneuver is reported. An essential contribution to such a test program is the gas dynamic simulation of the size and shape of the plumes emitting from the full-scale orbiter and booster main propulsion systems. The two major effects of the plume which must be simulated are: the interaction of the plume with the external flow field, and the direct impingement of the plumes on surfaces which are enveloped by the plume. To accomplish the objective of correct plume simulation, the similarity parameters developed by Herron and the requirement to match momentum flux per unit area between the model and the full-scale systems, were applied to the orbiter and booster propulsion systems.
The types of Doppler gravity data available for local as opposed to planetwide geophysical modeling are reviewed. Those gravity fields that are determined dynamically in orbit determination programs yield a smoothed representation of the local gravity field that may be used for quantitative modeling. An estimate of the difference between smoothed and true fields can be considered as a noise limitation in generating local gravity models. A nonlinear inversion for the geometry, depth, and density of the Mare Serenitatis mascon using an ellipsoidal model yielded a global least squares minimum in horizontal dimensions, depth, and thickness-density contrast product. It was subsequently found, by using a linear model, that there were an infinite number of solutions corresponding to various combinations of depth and lateral inhomogeneity. Linear modeling was performed by means of generalized inverse theory.
Design criteria, methods and data, were developed to permit effective design of acoustic cavities for use in regeneratively cooled OME-type engines. This information was developed experimentally from two series of motor firings with high-temperature fuel during which the engine stability was evaluated under various conditions and with various cavity configurations. Supplementary analyses and acoustic model testing were used to aid cavity design and interpretation of results. Results from this program clearly indicate that dynamic stability in regeneratively cooled OME-type engines can be ensured through the use of acoustic cavities. Moreover, multiple modes of instability were successfully suppressed with the cavity.
An operational computer program, the Procedures and Performance Program (PPP) which operates in conjunction with the Phase I Shuttle Procedures Simulator to provide a procedures recording and crew/vehicle performance monitoring capability was developed. A technical synopsis of each task resulting in the development of the Procedures and Performance Program is provided. Conclusions and recommendations for action leading to the improvements in production of crew procedures development and crew training support are included. The PPP provides real-time CRT displays and post-run hardcopy output of procedures, difference procedures, performance data, parametric analysis data, and training script/training status data. During post-run, the program is designed to support evaluation through the reconstruction of displays to any point in time. A permanent record of the simulation exercise can be obtained via hardcopy output of the display data and via transfer to the Generalized Documentation Processor (GDP). Reference procedures data may be transferred from the GDP to the PPP. Interface is provided with the all digital trajectory program, the Space Vehicle Dynamics Simulator (SVDS) to support initial procedures timeline development.
A multiple-degree-of-freedom takeoff and landing analysis, Flexible Aircraft TakeOff and Landing Analysis computer program (FATOLA), was used to predict the landing behavior of a rigid-body X-24B reentry research vehicle and of a flexible-body modified-delta-wing supersonic YF-12 research aircraft. The analytical predictions were compared with flight test data for both research vehicles. Predicted time histories of vehicle motion and attitude, landing-gear strut stroke, and axial force transmitted from the landing gear to the airframe during the landing impact and rollout compared well with the actual time histories. Based on the comparisons presented, the versatility and validity of the FATOLA program for predicting landing dynamics of aircraft has been demonstrated.
A technique for objectively evaluating different displays by sensitivity analysis is described. First, the mathematical model used to analyze static displays is developed. The technique is based on formulating functional relationships between the state variables and the variables observable in the display. The matrix of the partial derivatives of the display variables with respect to the state variables, together with the observer's acuity function, is used to calculate expected errors in the state vector estimation. The technique is expanded by the use of Kalman filtering to process a time series of observation vectors. This provides a tool for analyzing displays of dynamic processes by means of a dynamic display evaluation computer program. Results are reported using this program to simulate an Instrument Landing System approach.
The LOADS computer program L218 which calculates dynamic load coefficient matrices utilizing the force summation method is described. The load equations are derived for a flight vehicle in straight and level flight and excited by gusts and/or control motions. In addition, sensor equations are calculated for use with an active control system. The load coefficient matrices are calculated for the following types of loads: (1) translational and rotational accelerations, velocities, and displacements; (2) panel aerodynamic forces; (3) net panel forces; and (4) shears, bending moments, and torsions.
Topics covered involve a number of closely related tasks including: the development of several control loop and dynamic noise model computer programs for simulating microwave radiometer measurements; computer modeling of an existing stepped frequency radiometer in an effort to determine its optimum operational characteristics; investigation of the classical second order analog control loop to determine its ability to reduce the estimation error in a microwave radiometer; investigation of several digital signal processing unit designs; initiation of efforts to develop required hardware and software for implementation of the digital signal processing unit; and investigation of the general characteristics and peculiarities of digital processing noiselike microwave radiometer signals.
The objectives, expected results, approach, and FY 81 milestones for the Structures and Dynamics Division's research program are presented. This information will be useful in program coordination with other government organizations in areas of mutual interest.
The NASA-Langley Research Center is currently investigating the high angle-of-attack characteristics of a forward-swept wing fighter technology demonstrator in a cooperative program with the Defense Advanced Research Projects Agency. The program includes static and dynamic wind-tunnel force tests, free-flight model tests, spin-tunnel tests, and piloted simulation. Particular emphasis is placed on identifying the contributions of the forward-swept wing to the configuration aerodynamics at high angles of attack. Results are presented to illustrate the wing contributions in terms of aerodynamic stability, flow visualization, and observation of free-flight characteristics.
Static analysis, dynamic analysis, and computer programs are discussed. Spur gear formulae and involute profile development and deflection are also discussed.
Harmonic wave and wave front propagations in a graphite/epoxy laminate are investigated using a plate theory that includes transverse shear deformation. Transient waves produced by impact of a steel ball are studied experimentally and by using finite elements. The statically measured law of contact between the steel ball and the laminate is used in the finite element program to compute the dynamic contact force. It is found that use of this contact law in conjunction with the finite element modeling of the laminate yields excellent agreement with the experimental results.