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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Wind tunnel pressure signatures for a 0.0041-scale model of the space shuttle orbiter

Pressure signatures for a 0.0041-scale model of a space shuttle orbiter were measured in a wind tunnel at Mach numbers from 1.30 to 3.02. The model was tested at 10 deg and 25 deg angle of attack and roll angles were varied from 0 deg to 180 deg in 30 deg increments. Comparisons of sonic boom levels were made for a delta wing configuration and for the space shuttle orbiter which were assumed to have identical lengths and entry trajectories. The sonic boom levels for the orbiter were slightly higher than those for the delta wing orbiter. An example is presented showing that the existing data base for the delta wing orbiter can be used to predict the ground level sonic booms for the orbiter.

Mendoza, J. P.↗
NASA NTRS1980

Sunward flow in Jupiter's magnetosheath

The position of Voyager crossings of Jupiter's bow shock show a dependence on solar wind pressure to the -1/3 power. This dependence is used to calculate typical bow shock speeds of 50 km/s from Voyager solar wind plasma data. Since the bow shock and magnetopause move approximately in unison in response to solar wind pressure changes, the resulting movement of the magnetosheath at a sizeable fraction of the solar wind speed leads to reversed, sunward flow in large portions of the dayside region when the boundaries are expanding. Voyager 1 plasma data show evidence of such reversed flow.

Siscoe, G. L.↗
NASA NTRS1929

Wind tunnel pressure distribution tests on an airfoil with trailing edge flap

This report deals with pressure distribution tests on an airfoil with a conventional trailing edge flap. These tests were conducted in the Atmospheric Wind Tunnel of the National Advisory Committee for Aeronautics. Maximum chord loadings were obtained with the flap displaced downward and with the airfoil at large angles of attack. Greater changes were produced in the normal force and in the center of pressure travel by up-flap than by an equal down-flap displacement.

Wenzinger, Carl J↗
NASA NTRS1976

Simulation of the atmospheric boundary layer in the wind tunnel for modeling of wind loads on low-rise structures

The lower part of the atmospheric boundary layer (strong wind conditions) was simulated in low speed wind tunnel for the modeling of wind loads on low-rise structures. The turbulence characteristics of the turbulent boundary layer in the wind tunnel are compared with full scale measurements and with measurements made at NASA Wallops Flight Center. Wind pressures measured on roofs of a 1:70 scale model of a small single family dwelling were compared with results obtained from full scale measurements. The results indicate a favorable comparison between full scale and model pressure data as far as mean, r.m.s. and peak pressures are concerned. In addition, results also indicate that proper modeling of the turbulence is essential for proper simulation of the wind pressures.

Tieleman, H. W.↗
DOE OSTI2024

DCMIP2016: the tropical cyclone test case

This paper describes and analyzes the Reed–Jablonowski (RJ) tropical cyclone (TC) test case used in the 2016 Dynamical Core Model Intercomparison Project (DCMIP2016). This intermediate-complexity test case analyzes the evolution of a weak vortex into a TC in an idealized tropical environment. Reference solutions from nine general circulation models (GCMs) with identical simplified physics parameterization packages that participated in DCMIP2016 are analyzed in this study at 50 km horizontal grid spacing, with five of these models also providing solutions at 25 km grid spacing. Evolution of minimum surface pressure (MSP) and maximum 1 km azimuthally averaged wind speed (MWS), the wind–pressure relationship, radial profiles of wind speed and surface pressure, and wind composites are presented for all participating GCMs at both horizontal grid spacings. While all TCs undergo a similar evolution process, some reach significantly higher intensities than others, ultimately impacting their horizontal and vertical structures. TCs simulated at 25 km grid spacings retain these differences but reach higher intensities and are more compact than their 50 km counterparts. These results indicate that dynamical core choice is an essential factor in GCM development, and future work should be conducted to explore how specific differences within the dynamical core affect TC behavior in GCMs.

Willson, Justin L.↗
NASA NTRS1980

Observations of the dayside ionopause and ionosphere of Venus

Some of the principal features of the dayside solar wind ionosphere interaction at Venus are presented. The dayside ionopause and ionosphere are observed to respond dramatically to solar wind pressure variations. The ram pressure of the solar wind is manifested mainly as magnetic pressure just external to the subsolar ionopause, and the ionopause location is controlled principally by this pressure. The ionosheath field is observed to drape across the dayside ionosphere, and ionopause currents over most of the dayside usually act to exclude the high ionosheath field from the generally low-field ionosphere. Tenuous, warm ionospheric plasma is sometimes observed on field lines outside the ionopause current sheet, suggesting that this dayside ionospheric plasma can be transported to the nightside and into the Venus wake. Some of the magnetic and thermal plasma features of the dayside ionosphere are shown, and modeling and distribution of flux ropes, small scale helical magnetic structures, are discussed in the context of thermal plasma observations.

Elphic, R. C.↗
NASA NTRS1990

A correlative investigation of the propagation of ULF wave power through the dayside magnetosphere

Three different ULF wave phenomena (azimuthally polarized Pc 3 pulsations, radially polarized Pc 4 pulsations, and solitary Pc 5 pulsations related to solar wind pressure pulses) were studied. The main problems covered are: (1) how do magnetospheric Pc 3-4 pulsations, which appear to originate in the solar wind, enter the magnetosphere, and how is this wave energy transported throughout the magnetosphere once it enters; (2) what is the ULF response of the outer dayside magnetosphere to solar wind pressure pulses; and (3) how do Pc 3-4 pulsations modulate ELF-VLF emissions in the dayside magnetosphere.

Engebretson, Mark J.↗
NASA NTRS2013

Vandenberg Air Force Base Pressure Gradient Wind Study

Warning category winds can adversely impact day-to-day space lift operations at Vandenberg Air Force Base (VAFB) in California. NASA's Launch Services Program and other programs at VAFB use wind forecasts issued by the 30 Operational Support Squadron Weather Flight (30 OSSWF) to determine if they need to limit activities or protect property such as a launch vehicle. The 30 OSSWF tasked the AMU to develop an automated Excel graphical user interface that includes pressure gradient thresholds between specific observing stations under different synoptic regimes to aid forecasters when issuing wind warnings. This required the AMU to determine if relationships between the variables existed.

Shafer, Jaclyn A.↗
NASA NTRS1977

A distributed processing high data rate multiport wind-tunnel pressure measurement system

A multiport pressure measurement system has been developed for the high data rates and the in situ calibration of electronically scanned pressure (ESP) sensors. The system employs a stand-alone microcomputer, connected to a host computer, for data acquisition and preprocessing. The host computer provides several operational modes. Before each run the in situ calibration of each sensor is automatically performed. Using up to a maximum of 14 data acquisition and control units (DACU's), the system may be expanded from 16 to 10,752 pressure ports. Each DACU can make 20,000 measurements per second, average data, and perform statistical analyses before transferring data to the central unit. The system may be introduced into existing facilities and requires little user orientation.

Juanarena, D.↗
NASA NTRS1989

Further comparison of two synoptic surface wind and pressure analysis methods

The geostrophic stream and potential functions of Sangster and the derived flat pressure field of Pielke and Cram are further compared. A simple numerical experiment with an idealized mountain-atmosphere system compares the two methods and their sensitivity to lateral boundary conditions. The flat pressure field of Pielke and Cram is essentially equivalent to the stream-function of Sangster, although the two methods have different boundary condition formulations and resulting different sensitivities to these boundary conditions.

Cram, Jennifer M.↗