XB-70 flight test data comparisons with simulation predictions of inlet unstart and buzz
XB-70 flight test data comparison with simulated predictions of inlet unstart and buzz
Beaulieu, W. D.↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Helicopter derivative identification from analytic models and flight test data
Recent results of stability derivative identification from helicopter analytic models and flight test data are presented. Six and nine degree-of-freedom (DOF) linear models are identified from an analytic nonlinear helicopter simulation using a least square technique. The identified models are compared with the convectional partial differentiation method for obtaining derivatives to form the basis for interpretation of derivatives identified from flight data. Six degree-of-freedom models are identified from CH-53A and CH-54B flight data, using an extended Kalman filter modified to process several maneuvers simultaneously. The a priori derivative estimate is obtained by optimal filtering of the data and then using a least square method. The results demonstrate that a six DOF identified model is sufficient to determine the low frequency modes of motion, but a nine DOF rotor/body model is necessary for proper representation of short-term response.
Molusis, J. H.↗
Fracture toughness testing data: A technology survey and bibliography
Announced survey includes reports covering fracture toughness testing for various structural materials including information on plane strain and developing areas of mixed mode and plane strain test conditions. Bibliography references cite work and conclusions in fracture toughness testing and application of fracture toughness test data, and in fracture mechanics analysis.
Stuhrke, W. F.↗
Detailed requirements document for the radiant heat transfer facility post-test data reduction program
The requirements and functional specifications for a program to process test data obtained by the Radiant Heat Data Acquisition System are defined.
Brose, J. F.↗
F-111 natural laminar flow glove flight test data analysis and boundary layer stability analysis
An analysis of 34 selected flight test data cases from a NASA flight program incorporating a natural laminar flow airfoil into partial wing gloves on the F-111 TACT airplane is given. This analysis determined the measured location of transition from laminar to turbulent flow. The report also contains the results of a boundary layer stability analysis of 25 of the selected cases in which the crossflow (C-F) and Tollmien-Schlichting (T-S) disturbance amplification factors are correlated with the measured transition location. The chord Reynolds numbers for these cases ranges from about 23 million to 29 million, the Mach numbers ranged from 0.80 to 0.85, and the glove leading-edge sweep angles ranged from 9 deg to 25 deg. Results indicate that the maximum extent of laminar flow varies from 56% chord to 9-deg sweep on the upper surface, and from 51% chord at 16-deg sweep to 6% chord at 25-deg sweep on the lower. The results of the boundary layer stability analysis indicate that when both C-F and T-S disturbances are amplified, an interaction takes place which reduces the maximum amplification factor of either type of disturbance that can be tolerated without causing transition.
Runyan, L. J.↗
Validation of Transient Spacecraft Refueling Model with Gateway Breadboard Test Data
The ability to refuel spacecraft on-orbit is a key enabling technology for deep space human exploration. On-orbit refueling requires priming a pressurized liquid propellant from a source tank into fluid transfer lines at vacuum conditions, which could result in excessive surge pressures beyond the system’s qualified operating limits and potentially damage hardware. Therefore, it is imperative to employ numerical models during the development of flight hardware to parametrically characterize system performance over a wide range of operating conditions. Since priming transients are difficult to model accurately, it is important to validate those models with test data. As part of the Gateway bipropellant refueling system development, a simplified fluidic breadboard system was created using water as a simulant for fuel to support early program risk reduction of refueling operations. The objectives of breadboard testing were to gather performance data to characterize and demonstrate critical refueling operations and to validate numerical models that can be extended to predicting flight system performance. A description of the breadboard test system and the results of numerical model validation is presented. The model is shown to have very good agreement with test data.
Brian S Lusby↗
Evaluation of SSME test data reduction methods
Accurate prediction of hardware and flow characteristics within the Space Shuttle Main Engine (SSME) during transient and main-stage operation requires a significant integration of ground test data, flight experience, and computational models. The process of integrating SSME test measurements with physical model predictions is commonly referred to as data reduction. Uncertainties within both test measurements and simplified models of the SSME flow environment compound the data integration problem. The first objective of this effort was to establish an acceptability criterion for data reduction solutions. The second objective of this effort was to investigate the data reduction potential of the ROCETS (Rocket Engine Transient Simulation) simulation platform. A simplified ROCETS model of the SSME was obtained from the MSFC Performance Analysis Branch . This model was examined and tested for physical consistency. Two modules were constructed and added to the ROCETS library to independently check the mass and energy balances of selected engine subsystems including the low pressure fuel turbopump, the high pressure fuel turbopump, the low pressure oxidizer turbopump, the high pressure oxidizer turbopump, the fuel preburner, the oxidizer preburner, the main combustion chamber coolant circuit, and the nozzle coolant circuit. A sensitivity study was then conducted to determine the individual influences of forty-two hardware characteristics on fourteen high pressure region prediction variables as returned by the SSME ROCETS model.
Santi, L. Michael↗
Two-dimensional wind-tunnel tests of a NASA supercritical airfoil with various high-lift systems. Volume 2: Test data
Three high lift systems for a 9.3 percent blunt based, supercritical airfoil were designed, fabricated, and wind tunnel tested. A method for calculating the viscous flow about two dimensional multicomponent airfoils was evaluated by comparing its predictions with test data. A comparison of high lift systems derived from supercritical airfoils with high lift systems derived from conventional airfoils is presented. The high lift systems for the supercritical airfoil were designed to achieve maximum lift and consisted of: (1) a single slotted flap, (2) a double slotted flap and a leading edge slat, and (3) a triple slotted flap and a leading edge slat. Aerodynamic force and moment data and surface pressure data are presented for all configurations and boundary layer and wake profiles for the single slotted flap configuration. The wind-tunnel models, test facilities and instrumentation, and data reduction are described.
Omar, E.↗
Analysis and correlation with theory of rotor lift-limit test data
A wind tunnel test program to define the cruise performance and determine any limitations to lift and propulsive force of a conventional helicopter rotor is described. A 2.96 foot radius model rotor was used. The maximum lift and propulsive force obtainable from an articulated rotor for advance ratios of 0.4 to 0.67, and the blade load growth as the lift approaches the limit are determined. Cruise rotor performance for advance ratios of 0.4 to 0.67 and the sensitivity of the rotor forces and moments to rotor control inputs as the lift limit is approached are established.
Sheffler, M.↗
Comparison ofdvanced turboprop interior noise control ground and flight test data
Interior noise ground tests conducted on a DC-9 aircraft test section are described. The objectives were to study ground test and analysis techniques for evaluating the effectiveness of interior noise control treatments for advanced turboprop aircraft, and to study the sensitivity of the ground test results to changes in various test conditions. Noise and vibration measurements were conducted under simulated advanced turboprop excitation, for two interior noise control treatment configurations. These ground measurement results were compared with results of earlier UHB (Ultra High Bypass) Demonstrator flight sts with comparable interior treatment configurations. The Demonstrator is an MD-80 test aircraft with the left JT8D engine replaced with a prototype UHB advanced turboprop engine.
Simpson, Myles A.↗
Validation of Transient Spacecraft Refueling Model with Gateway Breadboard Test Data
The ability to refuel spacecraft on-orbit is a key enabling technology for deep space human exploration. On-orbit refueling requires priming a pressurized liquid propellant from a source tank into fluid transfer lines at vacuum conditions, which could result in excessive surge pressures beyond the system’s qualified operating limits and potentially damage hardware. Another source of potentially damaging surge pressures is the water hammer transient that occurs when the isolation valves are closed to pause or end the refueling operation. Therefore, it is imperative to employ numerical models during the development of flight hardware to parametrically characterize system performance over a wide range of operating conditions to minimize the risk of exceeding pressure limits during flight. Since rapid pressure transients can be difficult to model accurately, it is important to validate those models with test data. As part of the Gateway bipropellant refueling system development, a simplified fluidic breadboard system was created using water as a simulant for fuel to support early program risk reduction of refueling operations. The objectives of breadboard testing were to gather performance data to characterize and demonstrate critical refueling operations and to validate numerical models that can be extended to predicting flight system performance. A description of the breadboard test article and the results of numerical model validation is presented. The model is shown to have very good agreement with test data.
Refueling↗
Controlled Environmental Effects on Creep Test Data of Woven Fabric Webbings for Inflatable Space Modules
eveloping technologies for proposed lunar and Mars space exploration missions. Enhanced habitation sy g studied as potential habitats due to their inherent low mass and small launch volume. One goal of inflatable module research is quantification of the safe-life and end-of-life creep-strain spectrum. Full-scale pressurized inflatable modules are large, costly, and difficult to experimentally study. Therefore, material subcomponents are often studied as an alternative. An experimental thermally controlled long-term creep study of VectranTM webbings for application to inflatable modules is presented. Vectran fibers have high strength and low creep properties. High strength webbing materials are desirable for the load bearing restraint layer of inflatable modules because they are strong, flexible, and lightweight. Characterization of the creep behavior, safe-life, and end-of- life of webbing specimens will help quantify comparable life properties for inflatable modules. Several experimental multiple-year creep studies of webbing specimens in uncontrolled thermal environments have been conducted at NASA Langley Research Center. Experimental data obtained exhibits the classic creep-strain curve due to load, coupled with unique sinusoidal variation due to variation in temperature and humidity over daily and annual time periods. Results also have indicated that specimens fail within a year if the applied load is greater than 50 percent of the rated load. The primary goal of this study is to eliminate thermal effects from the creep data for a group of webbing specimens, and to allow uncontrolled thermal effects to influence the creep data of a second group of webbing specimens. Comparison of both sets of data will define how temperature influences creep data. A unique creep test facility was fabricated to facilitate the generation and comparison of the two sets of data. The facility consists of five creep test stands with an integrated heating and cooling system, and four creep test stands exposed to external environmental or ambient conditions. The facility contains displacement, temperature, humidity, and load sensors. Test specimens consist of one- inch wide, 48-inch long Vectran webbings rated at 12,500 pounds-per-inch. Experimental thermally controlled creep-strain data has been generated for two groups of webbing specimens. Applied load for all test stands was above 9000 lbs and greater than 50 percent of the rated load. Temperatures varied between 58˚F and 83˚F for the four test stands exposed to ambient conditions. Associated creep data exhibited the classic creep- strain profiles. The temperature was set to 72˚F for the five test stands in the controlled temperature environment. Creep data for tests with temperature control also exhibited the classic strain profiles. Data indicated that if the load is greater n thermal effects do not manifest. Therefore, creep tests with loads less than 50 percent of the rated load are planned for in the near future.
Kenner, Winfred S.↗
Outdoor flat-plate collector performance prediction from solar simulator test data
Solar collector performance data obtained from tests with a simulator was modified for real-life conditions. The data obtained with the simulator was corrected for the variable conditions of ambient temperature, wind, incident angle, flow rate, etc., that are encountered outdoors. Modification of simulator data was accomplished by combining experiment with theory. The technique was demonstrated by application to a spectrally selective and a nonselective type of collector. This kind of modified simulator collector performance data should be valuable in solar systems analysis and for collector performance ranking based on all-day calculated conditions.
Simon, F. F.↗
Additional correction of 4 percent Saturn 5 protuberance test data
Transonic wind tunnel background noise measurement for analysis of Saturn 5 model protuberance test data
Mc Canless, G. F., Jr.↗
Integrated Optical Design Analysis (IODA): New Test Data and Modeling Features
A general overview of the capabilities of the IODA ("Integrated Optical Design Analysis") exchange of data and modeling results between thermal, structures, optical design, and testing engineering disciplines. This presentation focuses on new features added to the software that allow measured test data to be imported into the IODA environment for post processing or comparisons with pretest model predictions. software is presented. IODA promotes efficient
Moore, Jim↗
Washington Air-Sea Interaction Research Facility Waves and Currents Test Data
This archive includes data from the University of Washington WASIRF (Washington Air-Sea Interaction Research Facility) flume. WASIRF is a laboratory testing tank at the Northwest National Marine Renewable Energy Center designed to investigate wind-wave-current interactions. It includes test data for simultaneous waves and current generation done at the WASIRF lab. A report included in the archive further details testing methodology. Wave and current data is provided in .dat files.
16 TIDAL AND WAVE POWER↗
Accounting for Proof Test Data in a Reliability Based Design Optimization Framework
This paper investigates the use of proof (or acceptance) test data during the reliability based design optimization of structural components. It is assumed that every component will be proof tested and that the component will only enter into service if it passes the proof test. The goal is to reduce the component weight, while maintaining high reliability, by exploiting the proof test results during the design process. The proposed procedure results in the simultaneous design of the structural component and the proof test itself and provides the designer with direct control over the probability of failing the proof test. The procedure is illustrated using two analytical example problems and the results indicate that significant weight savings are possible when exploiting the proof test results during the design process.
Ventor, Gerharad↗
Development of an unsteady aerodynamics model to improve correlation of computed blade stresses with test data
A reliable rotor aeroelastic analysis operational that correctly predicts the vibration levels for a helicopter is utilized to test various unsteady aerodynamics models with the objective of improving the correlation between test and theory. This analysis called Rotor Aeroelastic Vibration (RAVIB) computer program is based on a frequency domain forced response analysis which utilizes the transfer matrix techniques to model helicopter/rotor dynamic systems of varying degrees of complexity. The results for the AH-1G helicopter rotor were compared with the flight test data during high speed operation and they indicated a reasonably good correlation for the beamwise and chordwise blade bending moments, but for torsional moments the correlation was poor. As a result, a new aerodynamics model based on unstalled synthesized data derived from the large amplitude oscillating airfoil experiments was developed and tested.
Gangwani, S. T.↗