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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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At least 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Results of tests 0A12 and IA9 in the Ames Research Center unitary plan wind tunnels on an 0.030 scale model of the space shuttle vehicle 2A to determine aerodynamic loads, volume 16

Tests were conducted in the NASA/ARC Unitary Plan Wind Tunnels on an 0.030 scale replica of the space shuttle vehicle Configuration 2A. Aerodynamic loads data were obtained at Mach numbers from 0.6 to 3.5. The integrated vehicle was tested at angles of attack and sideslip from -8 degrees to +8 degrees. The isolated orbiter was tested at angles of attack from -15 degrees to +40 degrees and angles of sideslip from -10 degrees to +10 degrees as dictated by trajectory considerations. The effects of orbiter/external tank incidence angle and deflected control surfaces on aerodynamic loads were also investigated.

Spangler, R. H.↗
NASA NTRS1975

Structural analysis of wind turbine rotors for NSF-NASA Mod-0 wind power system

Preliminary estimates of vibratory loads and stresses in hingeless and teetering rotors for the proposed 100-kW wind power system are presented. Stresses in the shank areas of the 19-m (62.5-ft) blades are given for static, rated, and overload conditions. The teetering rotor has substantial advantages over the hingeless rotor with respect to shank stresses, fatigue life, and tower loading. A teetering rotor will probably be required in order to achieve a long service life in a large wind turbine exposed to periodic overload conditions.

Spera, D. A.↗
NASA NTRS1996

Full-scale S-76 rotor performance and loads at low speeds in the NASA Ames 80- by 120-Foot Wind Tunnel

A full-scale helicopter rotor test was conducted in the NASA Ames 80- by 120-Foot Wind Tunnel with a four-bladed S-76 rotor system. Rotor performance and loads data were obtained over a wide range of rotor shaft angles-of-attack and thrust conditions at tunnel speeds ranging from 0 to 100 kt. The primary objectives of this test were (1) to acquire forward flight rotor performance and loads data for comparison with analytical results; (2) to acquire S-76 forward flight rotor performance data in the 80- by 120-Foot Wind Tunnel to compare with existing full-scale 40- by 80-Foot Wind Tunnel test data that were acquired in 1977; (3) to evaluate the acoustic capability of the 80- by 120- Foot Wind Tunnel for acquiring blade vortex interaction (BVI) noise in the low speed range and compare BVI noise with in-flight test data; and (4) to evaluate the capability of the 80- by 120-Foot Wind Tunnel test section as a hover facility. The secondary objectives were (1) to evaluate rotor inflow and wake effects (variations in tunnel speed, shaft angle, and thrust condition) on wind tunnel test section wall and floor pressures; (2) to establish the criteria for the definition of flow breakdown (condition where wall corrections are no longer valid) for this size rotor and wind tunnel cross-sectional area; and (3) to evaluate the wide-field shadowgraph technique for visualizing full-scale rotor wakes. This data base of rotor performance and loads can be used for analytical and experimental comparison studies for full-scale, four-bladed, fully articulated rotor systems. Rotor performance and structural loads data are presented in this report.

Shinoda, Patrick M.↗
NASA NTRS1973

Results of tests OA12 and IA9 in the Ames Research Center Unitary Plan Wind Tunnels on an 0.030-scale model of the Space Shuttle Vehicle 2A to determine aerodynamic loads, volume 3

Tests were conducted in the NASA/ARC Unitary Plan Wind Tunnels during April and May 1973, on an 0.030-scale replica of the Space Shuttle Vehicle Configuration 2A. Aerodynamic loads data were obtained at Mach numbers from 0.6 to 3.5. The investigation included tests IA9A, B and C on the integrated (launch) configuration and tests OA12A and C on the isolated orbiter (entry configuration). The integrated vehicle was tested at angles of attack and sideslip from -8 degrees to +8 degrees. The isolated orbiter was tested at angles of attack from -15 degrees to +40 degrees and angles of sideslip from -10 degrees to +10 degrees to as dictated by trajectory considerations. The effects of orbiter/external tank incidence angle and deflected control surfaces on aerodynamic loads were also investigated.

Spangler, R. H.↗
NASA NTRS1976

Cable-load equalization system

Limited-slip differential, used to drive dual-cable winches, synchronizes winding speeds and ensures equal loading of both cables.

Benjamin, R. W.↗
DOE OSTI2026

Reductions in wind farm main bearing rating lives resulting from wake impingement

This paper studies the impacts of wake impingement on main bearing rating lives predicted during the wind turbine design stage. A computational tool chain was developed to explore and quantify these effects across a wind farm populated by 10 MW wind turbines. Wind field and turbine load modelling was undertaken using the Dynamiks Python package, including application of a dynamic wake meandering model. The ISO 281 basic bearing rating life formulation was subsequently applied in order to evaluate impacts from wake effects. Analyses included a two-turbine parametric analysis, followed by a full wind farm analysis undertaken for the TotalControl 32-turbine reference wind farm, including full wind rose simulations across all operational wind speeds. Site conditions were accounted for using a Weibull wind speed distribution and a range of parametric wind direction rose models. Results indicate that wind farm main bearing rating lives are negatively impacted by the effects of wake impingement, resulting in rating life reductions for the analysed wind farm of the order of 16 % on average and as much as 20 %–25 %, both for the locating main bearing. Despite these high sensitivities, it is important to note that these resultant rating lives (i.e. the predicted lives) still far exceed the standard wind turbine operational lifetimes of 20–30 years. Wake impacts were also found to be asymmetrically related to the side on which the rotor is impinged, suggesting that, for the main bearing, there may be a “better” side for wake impingement to occur. Rating life sensitivities to wind rose shape were also observed. While these findings must be interpreted with due consideration for the various methodological limitations present, they provide compelling evidence that wake effects at the wind farm level should necessarily be included when undertaking main bearing operational load modelling, rating life assessment, or other load-related analyses.

17 WIND ENERGY↗
NASA NTRS1980

Development of a facility for large-scale testing of multistory buildings

Current experimental research pertaining to response of structures subjected to lateral loads such as strong winds or earthquake motions is limited to either tests of single structural components or small scale multistory structures. The feasibility of developing a facility where large scale multistory structures could be loaded to failure is discussed. The test facility would consist of a series of hydraulic actuators mounted on reaction frames currently in use at the Marshall Space Flight Center for structural testing of spacecraft components. The actuators would be controlled from signals computed by an on-line analysis of measured data. This method of loading could be used to simulate inertial forces resisted by a structure behaving in the non linear range of response subjected to motion at the base or to impulses along the height as would occur during a strong earthquake or wind.

Abrams, D. P.↗
NASA NTRS1986

An investigation of tip planform influence on the aerodynamic load characteristics of semispan, upswept wing and wing-tip

A semi-span wing, equipped with an interchangeable tip, which was varied in planform and size was examined. Total wing aerodynamic loading was obtained from the wind tunnel scale system. The wing tip was mounted on a separate six-component strain gauge balance, which provided the aerodynamic loads on the tip. The tests were accomplished in the NASA Ames 7X10-Foot Wind Tunnel at a Mach number of 0.178. The aerodynamic load characteristics of the wing and of the tip were presented with the tip at several incidence angles relative to the wing inboard section.

Vanaken, Johannes M.↗
NASA NTRS1946

Altitude-Wind-Tunnel Investigation of Performance of Several Propellers on YP-47M Airplane at High Blade Loadings V - Curtiss 836-14C2-18R1 Four-Blade Propeller

An investigation of the performance of several propellers on the YP-47M airplane at high blade loadings has been conducted in the Cleveland altitude wind tunnel at the request of the Air Materiel Command, Army Air Forces. As part of the program, a study was made of a Curtiss 836-14C2-18R1 four-blade propeller. The investigation was made for a range of power coefficients from 0.10 to 1.00 at free-stream Mach numbers of 0.30, 0.40, and 0.50 for density altitudes from 10,000 to 45,000 feet, engine powers from 150 to 2500 brake horsepower, and for engine speeds from 1000 to 2900 rpm. The propeller efficiencies were obtained from force measurements and the blade thrust load distribution was obtained by two diametrically opposed slipstream survey rakes shown in this paper.

Saari, Martin J.↗
DOE OSTI2026

FOCAL Campaign II/III: Applying Active Hull Controls Using Tuned-mass Dampers/Hull Flexibility and Internal Loads

Campaign II and III of the Floating Offshore-wind Controls Advanced Laboratory Experimental Program (FOCAL) aimed to generate a dataset enabling the validation of the performance and loads of a scaled hull, with and without structural hull control. The floating platform was subjected to a variety of wave environments and controlled using tuned-mass dampers (TMDs) tuned to two of the systems natural frequencies (Platform Pitch and Tower-bending). The floating platform is fully instrumented to record a variety of parameters in real time such as platform dynamics, accelerations, and loads at different points in the structure. The test data considered was generated at the University of Maine's Harold Alfond Wind and Wave (W2) testing facility. This testing was focused only on validation of wave loading, and wind conditions were not considered. As such the platform does not support a working turbine, and instead supports a structure designed to have the same mass properties as the 1:70 IEA 15MW Reference turbine. The Load Cases (LC) considered in this testing campaign are as follows: LC 1.X - Platform Static Offset (TMD off); LC 2.X - Platform Free-decays (TMD off); LC 3.X - Wave Cases (Regular Wave, Irregular Wave, Pink Noise Wave) with and without TMDs active. Detailed properties on the model system are found in the following reference: Lenfest E., Floating Offshore-wind Controls Advanced Laboratory (FOCAL) Experimental Program - Campaigns 2 and 3: 1:70 Model-scale Testing of the IEA-Wind 15MW Reference Turbine and the VolturnUS-S Hull. UMaine ASCC Report Number 23-56-1183.

17 WIND ENERGY↗
NASA NTRS1975

Results of investigation IA110 on a 0.015-scale integrated configuration of the space shuttle vehicle in the arc 9 x 7 supersonic wind tunnel using models 67-TS and 49-0

An 0.015-scale space shuttle vehicle model was tested to investigate Orbiter wind bending, elevon panel loads, and elevon effectiveness. Mach numbers from 1.5 through 2.5 were investigated. Angles of attack and sideslip were varied from -8 degrees through +8 degrees. Post test analysis of raw wind tunnel data indicated a zero shift had occured in the wing bending and torsional gages during the test. The mechanism by which this shift occurred was not determined. Therefore, all the wind root bending and torsional moment data is suspect.

Chee, E.↗
NASA NTRS1984

Adaptation of two-dimensional transonic analysis code, TSFOIL, for use in modeling adaptive wall test sections

The effects of the elastic deformation of the wind tunnel wall held to a streamline-like shape were simulated numerically. The wall itself is simulated by a finite element model and is allowed to deform under the pressure loading developing in the wind tunnel with an airfoil model present. A modified version of the transonic analysis program, TSFOIL, is then used to determine the resulting flow field with the effects of the deformed wall included, the shape of the wall and the flow field. Once a result from a particular operating condition was obtained, the pressure distribution on the airfoil in the wind tunnel model is compared with solutions generated by TSFOIL in the free air mode.

Webb, J.↗
NASA NTRS1995

Pick-up ion pressure gradients modulating the solar wind dynamics

Neutral interstellar atoms penetrate deeply into the inner heliosphere before they become ionized by various processes. As ions they are picked-up by the frozen-in magnetic fields and are convected outwards with the solar wind plasma. Thereby the primary plasma flow is mass, momentum, and energy-loaded. The dynamics of the distant multi-constituent solar wind is, however, not solely determined by these loading processes, but is also affected by the wave-mediated pick-up ion pressure gradients derivable from the pick-up ion distribution function. The action of the radial components of these pressures essentially counter balances the decelerating effect of the solar wind momentum loading, diminishing strongly the deceleration of the distant solar wind. Furthermore the latitudinal components of the pick-up ion pressures induce latitudinal forces acting on the multiconstituent solar plasma outflow and inducing nonradial bulk flow components. The enforced nonradial outflow geometry on the upwind hemisphere may partly be responsible for the magnetic flux deficit which was claimed since several years in the PIONEER-10 magnetic flux data.

Fahr, Hans J.↗
NASA NTRS1994

Hybrid simulation of comet Shoemaker-Levy 9 interaction with Jovian bow shock

The interaction of the solar wind with comet Shoemaker-Levy 9 leading to the formation of the cometary magnetosphere and its interaction with the Jovian bow shock is simulated using a one dimensional hybrid code. The mass loading of the solar wind by the cometary ions leads to the formation of a bow shock behind which the plasma density is 2-3/cu cm and the electron temperature is 4 eV. The interaction of this system with the Jovian bow shock yields local enhancements of the magnetic field and the plasma density by factors of 4-5 and the electron temperature by 2-3.

Lipatov, A. S.↗
NASA NTRS1981

Test evaluation of a laminated wood wind turbine blade concept

A series of tests conducted on a root end section of a laminated wood wind turbine blade are reported. The blade to hub transition of the wood blade uses steel studs cast into the wood D spar with a filled epoxy. Both individual studs and a full scale, short length, root section were tested. Results indicate that the bonded stud concept is more than adequate for both the 30 year life fatigue loads and for the high wind or hurricane gust loads.

Faddoul, J. R.↗
NASA NTRS1976

Early operation experience on the ERDA/NASA 100 kW wind turbine

As part of the Energy Research and Development Administration (ERDA) wind energy program, NASA Lewis Research Center is testing an experimental 100-kW wind turbine. Rotor blade and drive shaft loads and tower deflection were measured during operation of the wind turbine at rated rpm. The blade loads measured are higher than anticipated. Preliminary results indicate that air flow blockage by the tower structure probably caused the high rotor blade bending moments.

Glasgow, J. C.↗
NASA NTRS1984

Interplanetary field enhancements in the solar wind - Evidence for cometesimals at 0.72 and 1.0 AU?

A new class of interplanetary magnetic disturbance has been identified which consists of a nearly symmetric rise and fall of the magnetic field surrounding a cusp-shaped maximum. These disturbances have been hypothesized to be caused by the mass-loading of the solar wind by small outgassing bodies. The clustering of these events in space suggests that not all the events are independent. Clustering is greatest at 0.72 AU because of one very strong family of events associated with the orbit of the asteroid 2201 0ljato. The events are larger at 0.72 AU than at 1 AU. The timing of the disturbances at both 1 AU and 0.72 AU relative to 0ljato suggests the presence of outgassing debris both in front of and behind the asteroid.

Arghavani, M. R.↗
NASA NTRS2015

Coupled CFD/CSD Analysis of an Active-Twist Rotor in a Wind Tunnel with Experimental Validation

An unsteady Reynolds averaged Navier-Stokes analysis loosely coupled with a comprehensive rotorcraft code is presented for a second-generation active-twist rotor. High fidelity Navier-Stokes results for three configurations: an isolated rotor, a rotor with fuselage, and a rotor with fuselage mounted in a wind tunnel, are compared to lifting-line theory based comprehensive rotorcraft code calculations and wind tunnel data. Results indicate that CFD/CSD predictions of flapwise bending moments are in good agreement with wind tunnel measurements for configurations with a fuselage, and that modeling the wind tunnel environment does not significantly enhance computed results. Actuated rotor results for the rotor with fuselage configuration are also validated for predictions of vibratory blade loads and fixed-system vibratory loads. Varying levels of agreement with wind tunnel measurements are observed for blade vibratory loads, depending on the load component (flap, lag, or torsion) and the harmonic being examined. Predicted trends in fixed-system vibratory loads are in good agreement with wind tunnel measurements.

Massey, Steven J.↗