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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 613 records · Page 34
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

A Framework for Characterizing the Risk of Ice Fall and Ice Throw from Small Wind Turbines

Small wind turbines rated up through 100 kW in size are typically deployed as distributed energy resources. Their proximity to populations, buildings, and other infrastructure can generate safety concerns regarding ice throw (ice detaching from operational turbines) and ice fall (ice detaching from a turbine during standstill or idling) even when the turbines are not installed in cold climates. This paper presents a data-driven approach to characterize and mitigate the potential risk from icing on small wind turbines. By identifying how likely it is that an icing event will occur each year, estimating the distances at which ice could throw or fall from the turbine, defining the risk context, and establishing risk management practices, small wind turbine developers and installers can help address communities’ safety concerns around ice throw and ice fall.

17 WIND ENERGY↗
DOE OSTI2023

Sink or Swim: A Tutorial on the Control of Floating Wind Turbines: Preprint

Within the rapidly growing wind energy sector, floating offshore wind turbines are expected to be the fastest growing portion. This is largely driven by the immense offshore wind resources that are mostly over deep water, where fixed-bottom concepts become cost prohibitive. However, compared to fixed-bottom wind turbines, floating wind turbines are more dynamic and exhibit potential instabilities, which requires advanced control technologies to ensure a safe and efficient operation. Beyond their existing objectives of maximizing power production while minimizing structural loads, floating wind turbine controllers must also avoid large platform oscillations and accommodate wave disturbances. This paper provides an overview of the challenges and opportunities in the control of floating offshore wind energy systems.

control↗
NASA NTRS1992

In-situ release of solar wind gases from lunar soil

A concept is described which has the potential to perform the in situ heating of the lunar regolith in order to release the solar wind gases. The poor thermal conductivity of the lunar soil is increased approximately 100-fold by the introduction of an artificial hydrogen atmosphere at 1 atm pressure enclosed in an inflatable structure. The leakage rate of H2 through the soil is minimal because of the close-packed nature of the soil and the design and operation of the facility.

Wittenberg, Layton J.↗
DOE OSTI2025

An AI-Based 3D Bat Movement Tracking System at Wind Energy Facilities Using Multi-Thermal Video Cameras

The poster at the 15th Wind Wildlife Research Meeting discusses how to leverage the potential of real-time thermal-imaging methodologies in quantifying nocturnal bat activities at wind turbines, using 3D computer vision techniques within a deep learning framework. This innovation enables the automatic detection and classification of bats, birds, and insects in thermal-imaging videos captured at wind turbine sites, facilitating efficient and accurate data analysis for enhanced understanding and mitigation of bat-wind turbine interactions.

AI↗
DOE OSTI2025

An AI-Based 3D Bat Movement Tracking System at Wind Energy Facilities Using Multi-Thermal Video Cameras

The talk at the NAWEA Wind Tech 2024 conference discusses how to leverage the potential of real-time thermal-imaging methodologies in quantifying nocturnal bat activities at wind turbines, using 3D computer vision techniques within a deep learning framework. This innovation enables the automatic detection and classification of bats, birds, and insects in thermal-imaging videos captured at wind turbine sites, facilitating efficient and accurate data analysis for enhanced understanding and mitigation of bat-wind turbine interactions.

AI↗
NASA NTRS1982

The polar ionosphere as a source of energetic magnetospheric plasma

Data are presented on an additional ionospheric source composed of ions flowing upward out of the high latitude polar cap with energies in the range of approximately 10 eV to more than about 100 eV. The data are from the energetic ion composition spectrometer (EICS) on board the Dynamics Explorer-1 satellite, launched in August 1981. It is noted that the results presented are not inconsistent with the existence of a polar wind of the type predicted by Axford (1968) since ions with energies less than about 1 eV would have been excluded from the instrument by the generally positive vehicle potential. The results suggest that the polar wind is either modified in mass composition and energy by some as yet unidentified process or is supplemented by a new unrelated source of plasma. What is more, owing to the higher energies, the energetic polar cap ions described here enter the plasma sheet at greater distances than Cowley (1980) estimated and probably represent a significant source of plasma for the maintenance of the plasma sheet.

Shelley, E. G.↗
NASA NTRS1974

Results of tests to determine the aerodynamic characteristics of two potential aeromaneuvering orbit-to-orbit shuttle (AMOOS) vehicle configurations in the NASA-Ames 3.5 foot hypersonic wind tunnel

An aerodynamic wind tunnel investigation was conducted in the NASA-Ames Research Center (ARC) 3.5-foot hypersonic facility to provide data for use in obtaining experimental force and static stability characteristics of two potential aeromaneuvering orbit-to-orbit shuttle (AMOOS) vehicle configurations. The experimental data were compared with the aerodynamic characteristics estimated using Newtonian theory, thus establishing the usefulness of these predictions. The candidate AMOOS configurations selected for the wind tunnel tests were the AMOOS 5B and HB configurations. Two flap configurations were tested for each candidate - a forward or compression surface flap and an aft or expansion flap. Photographs and sketches of the two configurations with different control surfaces are shown. It was determined that Newtonian theory generally predicted the aerodynamics of the 5B configuration with acceptable accuracy for all expansion flap deflections and for compression flap deflections less than or equal to 10 degrees. Flow separation upstream of large compression flap deflections was detected from the experimental data.

Ketter, F. C., Jr.↗
DOE OSTI2025

How Representative Are Uncrewed Aircraft System Measurements of the Convective Boundary Layer?

Abstract Uncrewed aircraft systems (UAS) demonstrate significant potential for filling data gaps in the atmospheric boundary layer. However, the extent to which UAS observations—typically vertical profiles taken over 15 min—are representative of the boundary layer as a whole remains poorly characterized. Using large eddy simulations (LES) of the daytime convective boundary layer (CBL), we quantify random errors in UAS measurements that occur due to insufficient statistical convergence of the time average to the true ensemble mean. Random errors in first‐order moments increase as the CBL becomes increasingly unstable, and are largest near the surface for most quantities. Errors are on the order of 2–6 m for wind speed, 15–60 for wind direction, 0.2–3 K for potential temperature, and 0.1–1 g for specific humidity, with errors in turbulent fluxes on the order of 50%–100%. Sampling strategies that mitigate random errors are discussed in light of our results.

Greene, Brian R. [Now at Verisk Extreme Event Solu↗
DOE OSTI2021

A forecast-driven decision-making model for long-term operation of a hydro-wind-photovoltaic hybrid system

Hydro-wind-photovoltaic (PV) hybrid system has the potential to increase the integration of renewable energy sources into an existing grid. For the long-term operation of the system, due to the non-storable nature of wind and PV power, it is essentially to decide the optimal long-term carryover storage of cascade reservoirs. However, it remains a challenge due to high uncertainties of long-term forecasts and complicated hydraulic/electrical relationships between cascade reservoirs. Here in this study, a forecast-driven decision-making model is proposed for the hybrid system, which converts the multi-stage long-term operation process into a two-stage operation problem (including current stage and carryover stage) to avoid using longer-horizon forecast information with lower accuracy. First, the carryover stage energy surfaces (CESs) considering the forecast uncertainties of wind, solar and hydro resources are proposed to characterize carryover stage benefit quantitatively. Then a CESs-based forward decision-making optimization model is developed to guide the long-term operation of a hydro-wind-photovoltaic hybrid system. The applications in a hydro-wind-PV hybrid system of Yalong River basin results show that: compared with conventional operation, 1) power generation increases 9.03%; 2) in terms of the carryover storages control, the reservoir impounding and drawdown timing are delayed, and the drawdown depth is increased, which can be used to formulate better reservoir operation rules.

13 HYDRO ENERGY↗
NASA NTRS1999

Follow-on Missions to SPARCLE

Global tropospheric wind observations are considered the number one unaccommodated atmospheric observation for the new series of NPOESS (National Polar Orbiting Environmental Satellite Series) platforms. The operational meteorology communities have long recognized the potential for improved forecasting skill if accurate wind observations were available around the globe. Recent analyses suggest that wind observations such as those that could be made by a space-based Doppler wind lidars; would even result in greater improvements than better temperature soundings. In this paper we present a roadmap that begins with the NASA approved SPAce Readiness Coherent Lidar Experiment (SPARCLE) and ends with an operational DWL (Doppler Wind Lidar) on an NPOESS platform.

Emmitt, G. D.↗
NASA NTRS1990

Forbidden-line emission and infrared excesses in T Tauri stars - Evidence for accretion-driven mass loss?

It is suggested that disk accretion provides the requisite external source to power the winds of T Tauri stars. As a test of this hypothesis, a potential accretion diagnostic for a representative sample of stars is compared to diagnostics of the wind strength. The luminosity of H-alpha, formed in the inner wind, and the luminosity of the forbidden emission lines, formed in the outer wind, are used as wind diagnostics, while the excess infrared luminosity is used as a potential accretion diagnostic. It is found that forbidden-line O I 6300 A and H-alpha line luminosities are correlated with each other over two orders of magnitude; this is interpreted as the indication of a wide range of mass-loss rates among the given sample of T Tauri stars. The luminosity of each of these lines is also found to be correlated with excess infrared luminosity. However, neither the forbidden nor the H-alpha luminosity is well correlated with the photospheric luminosity, leading to a conclusion that it is the disk, not the star, which primarily determines the strength of wind indicators in T Tauri stars.

Cabrit, Sylvie↗
NASA NTRS1979

Use of global atmospheric data sets to test quasi-geostrophic eddy momentum flux convergence

The quasi-geostrophic relation between the fluxes of momentum, potential vorticity, and potential temperature is tested with global sets of atmospheric wind and temperature data by computing the convergence of momentum flux as a residual of the potential temperature and potential vorticity flux and comparing it to the momentum flux convergence computed directly. It is shown that in the troposphere between 18 N and 74 N the observed momentum flux convergence differs from the quasi-geostrophic convergence by 25%-60%, with the larger errors only occurring where the convergence is small. These results indicate that momentum flux convergence obtained from quasi-geostrophic theory is adequate for qualitative studies of the general circulation, and is comparable in accuracy to values obtained in general circulation models. For simple climate models and qualitative process studies, it can thus provide a useful approach.

Heck, W. J.↗
NASA NTRS2012

An Extreme X-ray Disk Wind in the Black Hole Candidate IGR J17091-3624

Chandra spectroscopy of transient stellar-mass black holes in outburst has clearly revealed accretion disk winds in soft, disk-dominated states, in apparent anti-correlation with relativistic jets in low/hard states. These disk winds are observed to be highly ionized. dense. and to have typical velocities of approx 1000 km/s or less projected along our line of sight. Here. we present an analysis of two Chandra High Energy Transmission Grating spectra of the Galactic black hole candidate IGR J17091-3624 and contemporaneous EVLA radio observations. obtained in 2011. The second Chandra observation reveals an absorption line at 6.91+/-0.01 keV; associating this line with He-like Fe XXV requires a blue-shift of 9300(+500/-400) km/ s (0.03c. or the escape velocity at 1000 R(sub schw)). This projected outflow velocity is an order of magnitude higher than has previously been observed in stellar-mass black holes, and is broadly consistent with some of the fastest winds detected in active galactic nuclei. A potential feature at 7.32 keV, if due to Fe XXVI, would imply a velocity of approx 14600 km/s (0.05c), but this putative feature is marginal. Photoionization modeling suggests that the accretion disk wind in IGR J17091-3624 may originate within 43,300 Schwarzschild radii of the black hole, and may be expelling more gas than accretes. The contemporaneous EVLA observations strongly indicate that jet activity was indeed quenched at the time of our Chandra observations. We discuss the results in the context of disk winds, jets, and basic accretion disk physics in accreting black hole systems

King, A. L.↗
NASA NTRS1976

Applications of the real-time data analysis system in the Ames 40- by 80-foot wind tunnel

The first major overhaul and refurbishment of the Ames 40- by 80-foot wind tunnel since it was put into operation in 1944 was recently completed. A substantial part of this refurbishment was devoted to providing this wind tunnel with a modern real time data acquisition and analysis system to increase the safety, efficiency, and accuracy of experimental investigations in this facility. Background leading to the requirements for the new system, major elements of the system, and some of the applications of the system are summarized. The potential of computerized data acquisition systems for wind tunnels in terms of long term trends in hardware and software costs, and the constraints which must be dealt with to achieve the full potential of computerized data acquisition systems are discussed.

Kelly, M. W.↗
DOE OSTI2022

A New Era for Solar and Storage: Partnering for Continued Success

Solar energy has grown faster than experts projected. Energy storage technologies are poised to repeat that success, enabling a partnership to keep the lights on even after the sun sets. As current impacts and growing threats of climate change become more visible and the world accelerates efforts to adopt new clean-energy technology, electricity generation from solar and wind is playing an increasing role in the energy system. However, it can be confusing - we hear that solar has great potential, but we also hear that solar and wind are too small to make a meaningful difference, providing just 3% and 6% of the world's electricity in 2020, respectively (1). What is the reality and what can we expect in the coming years? This article focuses on solar, but wind has an equally impressive and interesting story. This article reviews how prices for solar have dropped dramatically and deployment has increased correspondingly to the point where solar is almost half of the new electricity generating capacity being installed globally today. It shows how solar-generated electricity has grown to the point where we need to pair it with storage or other strategies for balancing electricity supply and demand. The article also explores how lithium-ion batteries are replicating solar technology's big success and discusses new storage technologies that are being developed.

14 SOLAR ENERGY↗
NASA NTRS1997

Modeling of the Coupled Magnetospheric and Neutral Wind Dynamos

Over the past four years of funding, SRI, in collaboration with the University of Texas at Dallas, has been involved in assessing the influence of thermospheric neutral winds on the electric field and current systems at high latitudes. The initial direction of the project was to perform a set of numerical experiments concerning the contribution of the magnetospheric and neutral wind dynamo processes, under specific boundary conditions, to the polarization electric field and/or the field-aligned current distribution at high latitudes. To facilitate these numerical experiments we developed a numerical scheme that relied on using output from the NCAR Thermosphere-Ionosphere General Circulation Model (NCAR-TIGCM), expanding them in the form of spherical harmonics and solving the dynamo equations spectrally. Once initial calculations were completed, it was recognized that the neutral wind contribution could be significant but its actual contribution to the electric field or currents depended strongly on the generator properties of the magnetosphere. Solutions to this problem are not unique because of the unknown characteristics of the magnetospheric generator, therefore the focus was on two limiting cases. One limiting case was to consider the magnetosphere as a voltage generator delivering a fixed voltage to the high-latitude ionosphere and allowing for the neutral wind dynamo to contribute only to the current system. The second limiting case was to consider the magnetosphere as a current generator and allowing for the neutral wind dynamo to contribute only to the generation of polarization electric fields. This work was completed and presented at the l994 Fall AGU meeting. The direction of the project then shifted to applying the Poynting flux concept to the high-latitude ionosphere. This concept was more attractive as it evaluated the influence of neutral winds on the high-latitude electrodynamics without actually having to determine the generator characteristics of the magnetosphere. The influence of the neutral wind was then determined not by estimating how much electric potential or current density it provides, but by determining the contribution of the neutral wind to the net electromagnetic energy transferred between the ionosphere and magnetosphere. The estimate of the net electromagnetic energy transfer and the role of the neutral winds proves to be a more fundamental quantity in studies of magnetosphere- ionosphere coupling also showed that by using electric and magnetic field measurements from the HILAT satellite, the Poynting flux could be a measurable quantity from polar-orbiting, low- altitude spacecraft. Through collaboration with Dr. Heelis and others at UTD and their expertise of the electric field measurements on the DE-B satellite, an extensive analysis was planned to determine the Poynting flux from the DE-B measurements in combination with a modeling effort to help interpret the observations taking into account the coupled magnetosphere-ionosphere.

Thayer, Jeffrey P.↗
NASA NTRS2011

Use of Smoothed Measured Winds to Predict and Assess Launch Environments

Since many of the larger launch vehicles are operated near their design limits during the ascent phase of flight to optimize payload to orbit, it often becomes necessary to verify that the vehicle will remain within certification limits during the ascent phase as part of the go/no-go review made prior to launch. This paper describes the approach used to predict Ares I-X launch vehicle structural air loads and controllability prior to launch which represents a distinct departure from the methodology of the Space Shuttle and Evolved Expendable Launch Vehicle (EELV) programs. Protection for uncertainty of key environment and trajectory parameters is added to the nominal assessment of launch capability to ensure that critical launch trajectory variables would be within the integrated vehicle certification envelopes. This process was applied by the launch team as a key element of the launch day go/no-go recommendation. Pre-launch assessments of vehicle launch capability for NASA's Space Shuttle and the EELV heavy lift versions require the use of a high-resolution wind profile measurements, which have relatively small sample size compared with low-resolution profile databases (which include low-resolution balloons and radar wind profilers). The approach described in this paper has the potential to allow the pre-launch assessment team to use larger samples of wind measurements from low-resolution wind profile databases that will improve the accuracy of pre-launch assessments of launch availability with no degradation of mission assurance or launch safety.

Cordova, Henry S.↗
NASA NTRS1984

Wake profile measurements of fixed and oscillating flaps

Although the potential of laser velocimetry for the non-intrusive measurement of complex shear flows has long been recognized, there have been few applications in other small, closely controlled laboratory situations. Measurements in large scale, high speed wind tunnels are still a complex task. To support a study of periodic flows produced by an oscillating edge flap in the Ames eleven foot wind tunnel, this study was done. The potential for laser velocimeter measurements in large scale production facilities are evaluated. The results with hot wire flow field measurements are compared.

Owen, F. K.↗