Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Wind Speed”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,657 records · Page 92
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Best Practices for the Validation of U.S. Offshore Wind Resource Models

This report presents a comprehensive set of best practices for working with both modeled and measured US offshore wind resource data sets. We specifically target two key questions in this report. First, what are the best data sources and methods for validating modeled wind resource estimates? Second, what are the best methods for vertically extrapolating near-surface wind speed measurements to heights that span the rotor-swept area of modern offshore wind turbines?

17 WIND ENERGY↗
DOE OSTI2025

WREF Halo Streamline scanning lidar / Derived data / RHI

This dataset contains streamwise velocity retrieved from the Range Height Indicator (RHI) scans done by the UC Davis scanning Lidar. The quality control of the radial wind speed is performed following the algorithm of Beck & Kuhn (2017). Instantaneous realizations characterized by wind misalignment greater than 60 degrees (based on the closest VAD scan in time) are discarded.

17 WIND ENERGY↗
DOE OSTI2025

A Review of Offshore Methane Quantification Methodologies

Since pre-industrial times, anthropogenic methane emissions have increased and are partly responsible for a changing global climate. Natural gas and oil extraction activities are one significant source of anthropogenic methane. While methods have been developed and refined to quantify onshore methane emissions, the ability of methods to directly quantify emissions from offshore production facilities remains largely unknown. Here, we review recent studies that have directly measured emissions from offshore production facilities and critically evaluate the suitability of these measurement strategies for emission quantification in a marine environment. The average methane emissions from production platforms measured using downwind dispersion methods were 32 kg h−1 from 188 platforms; 118 kg h−1 from 104 platforms using mass balance methods; 284 kg h−1 from 151 platforms using aircraft remote sensing; and 19,088 kg h−1 from 10 platforms using satellite remote sensing. Upon review of the methods, we suggest the unusually large emissions, or zero emissions observed could be caused by the effects of a decoupling of the marine boundary layer (MBL). Decoupling can happen when the MBL becomes too deep or when there is cloud cover and results in a stratified MBL with air layers of different depths moving at different speeds. Decoupling could cause: some aircraft remote sensing observations to be biased high (lower wind speed at the height of the plume); the mass balance measurements to be biased high (narrow plume being extrapolated too far vertically) or low (transects miss the plume); and the downwind dispersion measurements much lower than the other methods or zero (plume lofting in a decoupled section of the boundary layer). To date, there has been little research on the marine boundary layer, and guidance on when decoupling happens is not currently available. We suggest an offshore controlled release program could provide a better understanding of these results by explaining how and when stratification happens in the MBL and how this affects quantification methodologies.

Riddick, Stuart N. (ORCID:0000000316841843)↗
DOE OSTI2026

Lidar Measurements and High-Resolution Mesoscale Modeling of Coastally Trapped Disturbances off the Coast of California

Coastally Trapped disturbances (CTDs) are shifts in wind direction from the pre-dominant direction to equatorward to poleward for a period of time. These CTDs occur during the warm season off the California coast and impact coastal weather conditions and planned offshore wind plants. This study assesses the characteristics of CTD events as observed by lidar and other offshore buoys, then evaluates the ability of modeling systems to capture the correct characteristics, leveraging model output from the High-Resolution Rapid Refresh (HRRR) operational modeling system and the NOW-23 (National Offshore Wind) model dataset. CTDs were analyzed for October 2020 and May through to October of 2021, identifying 18 unique CTD events, confirmed by a nearby National Data Buoy Center (NDBC) buoy. The HRRR model captured most of these events, but the NOW-23 model output contained only 12 events. Composites of the wind, temperature, and pressure perturbations pre-, during, and post-event demonstrated the diminishment in wind speed, particularly for the alongshore component. Although the NOW-23 model captured the alongshore wind component and pressure perturbations well, the cross-shore wind component and temperature perturbations varied substantially. When the turbulent kinetic energy deviation and wind shear was positive across all levels pre-event, the NOW-23 modeling system was less likely to capture the CTD event. In contrast, the events that were captured by the model tended to have negative wind shear aloft pre-event.

coastal meteorology↗
NASA NTRS1973

The elevation, slope, and curvature spectra of a wind roughened sea surface

The elevation, slope and curvature spectra are defined as a function of wave number and depend on the friction velocity. There are five wave number ranges of definition called the gravity wave-gravity equilibrium range, the isotropic turbulence range, the connecting range due to Leykin Rosenberg, the capillary range, and the viscous cutoff range. The higher wave number ranges are strongly wind speed dependent, and there is no equilibrium (or saturated) capillary range, at least for winds up to 30 meters/sec. Some properties of the angular variation of the spectra are also found. For high wave numbers, especially in the capillary range, the results are shown to be consistent with the Rayleigh-Rice backscattering theory (Bragg scattering), and certain properties of the angular variation are deduced from backscatter measurements.

Pierson, W. J., Jr.↗
NASA NTRS1984

Transient behavior of flare-associated solar wind. II - Gas dynamics in a nonradial open field region

Transient behavior of flare-associated solar wind in the nonradial open field region is numerically investigated, taking into account the thermal and dynamical coupling between the chromosphere and the corona. A realistic steady solar wind is constructed which passes through the inner X-type critical point in the rapidly diverging region. The wind speed shows a local maximum at the middle, O-type, critical point. The wind's density and pressure distributions decrease abruptly in the rapidly diverging region of the flow tube. The transient behavior of the wind following flare energy deposition includes ascending and descending conduction fronts. Thermal instability occurs in the lower corona, and ascending material flows out through the throat after the flare energy input ceases. A local density distribution peak is generated at the shock front due to the pressure deficit just behind the shock front.

Nagai, F.↗
NASA NTRS1984

Numerical and experimental studies of particle flow in a high-pressure boundary-layer wind tunnel

The approach was to simulate the surface environment of Venus as closely as practicable and to conduct experiments to determine threshold wind speeds, particle flux, particle velocities, and the characteristics of various aeolian bedforms. The Venus Wind Tunnel (VWT) is described and the experimental procedures that were developed to make the high-pressure wind tunnel measurements are presented. In terrestrial simulations of aeolian activity, it is possible to conduct experiments under pressures and temperatures found in natural environments. Because of the high pressures and temperatures, Venusian simulations are difficult to achieve in this regard. Consequently, extrapolation of results to Venue potentially involves unknown factors. The experimental rationale was developed in the following way: The VWT enables the density of the Venusian atmosphere to be reproduced. Density is the principal atmospheric property for governing saltation threshold, particle flux, and the ballistics of airborne particles (equivalent density maintains dynamic similarity of gas flow). When operated at or near Earth's ambient temperature, VWT achieves Venusian atmospheric density at pressures of about 30 bar, or about one third less than those on Venus, although still maintaining dynamic similarity to Venus.

White, B. R.↗
NASA NTRS1986

On Blockage Corrections for Two-dimensional Wind Tunnel Tests Using the Wall-pressure Signature Method

The Wall-Pressure Signature Method for correcting low-speed wind tunnel data to free-air conditions has been revised and improved for two-dimensional tests of bluff bodies. The method uses experimentally measured tunnel wall pressures to approximately reconstruct the flow field about the body with potential sources and sinks. With the use of these sources and sinks, the measured drag and tunnel dynamic pressure are corrected for blockage effects. Good agreement is obtained with simpler methods for cases in which the blockage corrections were about 10% of the nominal drag values.

Allmaras, S. R.↗
NASA NTRS1989

A frontal cyclogenesis case study from Seasat scatterometer data

In June 1978, the Seasat satellite was launched carrying, among other instruments, the Seasat-A scatterometer system (SASS), which produced ambiguous wind speed and direction data at the ocean surface. A fifteen day subset of dealiased wind vector data with the inherent ambiguities removed was produced for the period of September 6-20, 1978. On September 8, SASS began to observe a development of frontal cyclogenesis in the South Pacific off the east coast of New Zealand, in an area of few surface observations. A large mature cyclone contained weak warm and cold fronts and an occlusion with a strong horizontal wind shear. Satellite imagery shows that a strong upper-level jet streak was moving rapidly over the area of the surface frontal occlusion and as the jet passed over this area a new vortex formed. This cyclogenesis event was studied using 50-km resolution scatterometer surface wind data. High-resolution fields of wind vectors, divergence and vorticity are computed and plotted from the scatterometer data to study the structure and development of the newly formed cyclonic vortex, not otherwise possible using conventional observations.

Cunningham, Glenn F.↗
NASA NTRS1993

Modeling the Arecibo nighttime F2 layer. I - Overhead properties

The paper extends the servo model of Rishbeth et al. (1978) and applies it to fit the height and plasma density of the nighttime F2 layer, as measured from the Arecibo Observatory during solar maximum by Burnside (1984). The model equations are integrated numerically to fit the observed peak height and density. The model adequately reproduces the observed behavior of the F2 layer. The additional terms in the extended servo-height equation affect the peak height computation by no more than 10 percent on average. The applied current is generally eastward though it becomes westward during the postmidnight collapse or descent of the layer. Differences between model and optically measured meridional wind speeds appear to be related to the presence of large vertical shears in the wind. The observed peak density can be reproduced to within 20 to 40 percent accuracy. Variable plasmaspheric fluxes of the order of 10 exp 13/sq m s contribute to the maintenance and variability of the nighttime peak density.

Melendez-Alvira, D. J.↗
NASA NTRS1942

High-Speed Tests of Conventional Radial-Engine Cowlings

The drag characteristics of eight radial-engine cowlings have been determined over a wide speed range in the NACA 8-foot high-speed wind tunnel. The pressure distribution over all cowlings was measured, to and above the speed of the compressibility burble, as an aid in interpreting the force tests. One-fifth-scale models of radial-engine cowlings on a wing-nacelle combination were used in the tests.

Robinson, Russell G↗
NASA NTRS2004

Winds From Hot Star Disks

In this talk I will briefly review the observational motivation and evidence for mass loss from disks around hot stars. Direct evidence for these outflows comes from line profiles in, eg. young stellar objects. Indirect evidence comes from the implied mass loss rates and wind speeds, along with dynamical models which can account for these properties. Mechanisms for disk wind driving include thermal, radiation pressure, and MHD. These will be reviewed and discussed, as will the relation to non-disk winds, and to disk winds in other contexts.

Kallman, Timothy↗
NASA NTRS1939

High-Speed Tests of Radial-Engine Cowlings

The drag characteristics of eight radial-engine cowlings have been determined over a wide speed range in the N.A.C.A. 8-foot high-speed wind tunnel. The pressure distribution over all cowlings was measured, to and above the speed of the compressibility burble, as an aid in interpreting the force tests. One-fifth-scale models of radial-engine cowlings on a wing-nacelle combination mere used in the tests.

Robinson, Russell G.↗
NASA NTRS2012

Observations of C-band Brightness Temperature from the Hurricane Imaging Radiometer (HIRAD) During GRIP

HIRAD is a new technology developed by NASA/MSFC, in partnership with NOAA and the Universities of Central Florida, Michigan, and Alabama-Huntsville. HIRAD is designed to measure wind speed and rain rate over a wide swath in heavy-rain, strong-wind conditions. HIRAD is expected to eventually fly routinely on unmanned aerial vehicles (UAVs) such as Global Hawk over hurricanes threatening the U.S. coast and other Atlantic basin areas, and possibly in the Western Pacific as well. HIRAD first flew on GRIP in 2010 and is planned to fly 2012-14 on the NASA Hurricane and Severe Storm Sentinel (HS3) missions on the Global Hawk, a high-altitude UAV. HIRAD technology will eventually be used on a satellite platform to extend the dynamical range of Ocean Surface Wind (OSV) observations from space.

Miller, Timothy L.↗
NASA NTRS2014

Configuration and Evaluation of a Dual-Doppler 3-D Wind Field System

Current LSP, GSDO, and SLS space vehicle operations are halted when wind speeds from specific directions exceed defined thresholds and when lightning is a threat. Strong winds and lightning are difficult parameters for the 45th Weather Squadron (45 WS) to forecast, yet are important in the protection of customer vehicle operations and the personnel that conduct them. A display of the low-level horizontal wind field to reveal areas of high winds or convergence would be a valuable tool for forecasters in assessing the timing of high winds, or convection initiation and subsequent lightning occurrence. This is especially important for areas where no weather observation platforms exist. Developing a dual-Doppler radar capability would provide such a display to assist forecasters in predicting high winds and convection initiation. The wind fields can also be used to initialize a local mesoscale numerical weather prediction model to help improve the model forecast winds, convection initiation, and other phenomena. The 45 WS and NWS MLB tasked the Applied Meteorology Unit (AMU) to develop a dual- Doppler wind field display using data from the 45th Space Wing radar, known as the Weather Surveillance Radar (WSR), NWS MLB Weather Surveillance Radar 1988 Doppler (KMLB), and the Orlando International Airport Terminal Doppler Weather Radar (KMCO). They also stipulated that the software used should be freely available. The AMU evaluated two software packages and, with concurrence from NWS MLB and the 45 WS, chose the Warning Decision Support System-Integrated Information (WDSS-II). The AMU collected data from two significant weather cases: a tornadic event on 14 April 2013 and a severe wind and hail event on 12 February 2014. For the 14 April case, the data were from WSR and KMLB. For the 12 February case, the data were from KMCO and KMLB. The AMU installed WDSS-II on a Linux PC, then processed and quality controlled the radar data for display and analysis using WDSS-II tools. Because of issues with de-aliasing the WSR velocity field, the AMU did not use data from this radar in this study and only analyzed the 12 February case. Merging the data to create the dual-Doppler analysis involved several steps. The AMU used instructions from the WDSS-II website and discussion forum to determine the correct tools to use for the analysis, and was successful in creating a merged reflectivity field, which was critical to the success of creating a merged velocity field. However, the AMU was unable to create a merged velocity field. The AMU researched the WDSS-II forum for discussions on similar issues, asked questions on the forum, and tested different options and values in the merger tool with no success. Developing a dual-Doppler wind field was the main goal of this task, but that was not accomplished. It could be an issue of not using the correct options or the correct value for the options used, or there could be issues with the radar data. There is a follow-on AMU task to install the operational version of WDSS-II in the NWS MLB office. This will provide more opportunities to try different options and input values in order to create a merged wind field from KMCO and KMLB.

Doppler radar↗
NASA NTRS2009

Validation of Community Models: Identifying Events in Space Weather Model Timelines

I develop and document a set of procedures which test the quality of predictions of solar wind speed and polarity of the interplanetary magnetic field (IMF) made by coupled models of the ambient solar corona and heliosphere. The Wang-Sheeley-Arge (WSA) model is used to illustrate the application of these validation procedures. I present an algorithm which detects transitions of the solar wind from slow to high speed. I also present an algorithm which processes the measured polarity of the outward directed component of the IMF. This removes high-frequency variations to expose the longer-scale changes that reflect IMF sector changes. I apply these algorithms to WSA model predictions made using a small set of photospheric synoptic magnetograms obtained by the Global Oscillation Network Group as input to the model. The results of this preliminary validation of the WSA model (version 1.6) are summarized.

MacNeice, Peter↗
NASA NTRS2004

A Search for the Solar Sources of High-Speed Streams

The original Grant was intended to support backward mapping of the stream structures observed at 1 AU by the WIND spacecraft using the observed wind speeds so that solar sources of the streams could be explored. Realizing that backwards mapping was unlikely to produce reasonable results inside of about 30 Rs, we let a subcontract to Mikic and Linker at SAIC who had developed a MHD code to cover the distance between the lower corona and 30 Rs. We used IPS measurements made by our Co-I Andy Breen to try to establish a correlation between the mapped-back streams and IPS determinations of the stream sources. We report the results of these portions of the program and then explain the progress on studies which were proposed to give insight into stream sources by exploiting the alpha/proton abundance ratios observed from WIND.

Source record↗