SEARCH · Engineering Papers

Results for “horizontal”

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.

SourceResearch connectionFrom yearThrough year

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

At least 271 records · Page 15

All sources NASA NTRS DOE OSTI

NASA NTRS1987

Effects of combining vertical and horizontal information into a primary flight display

A ground-based aircraft simulation study was conducted to determine the effects of combining vertical and horizontal flight information into a single display. Two display configurations were used in this study. The first configuration consisted of a Primary Flight Display (PFD) format and a Horizontal Situation Display (HSD) with the PFD displayed conventionally above the HSD. For the second display configuration, the HSD format was combined with the PFD format. Four subjects participated in this study. Data were collected on performance parameters, pilot-control inputs, auditory evoked response parameters (AEP), oculometer measurements (eye-scan), and heart rate. Subjective pilot opinion was gathered through questionnaire data and scorings for both the Subjective Workload Assessment Technique (SWAT) and the NASA Task Load Index (NASA-TLX). The results of this study showed that, from a performance and subjective standpoint, the combined configuration was better than the separate configuration. Additionally, both the eye-transition and eye-dwell times for the separate HSD were notably higher than expected, with a 46% increase in available visual time when going from double to single display configuration.

Abbott, Terence S.↗

NASA NTRS1988

Effect of computed horizontal diffusion coefficients on two-dimensional N2O model distributions

The effects of horizontal diffusion coefficients K(yy) and K(yz), computed directly from the residual circulation, on the N2O distribution in a photochemical model were investigated, using a modified version of the two-dimensional model of Guthrie et al. (1984). The residual circulation was computed using the NMC's temperature data and the heating rates reported by Rosenfield et al. (1987). As compared with the effect of the residual circulation alone, the use of horizontal diffusion coefficients produced substantial changes in the N2O distribution and increased the N2O's lifetime values by a few percent. It is suggested that trace gases, such as CH4, CFCl3, CF2Cl2, CH3Cl, and CCl4, which impact the NO(x), HO(x), and Cl(x) radical distributions and therefore ozone, will be influenced in a similar manner by the addition of more realistic diffusion fields.

Jackman, Charles H.↗

NASA NTRS1988

Multiple populations on the horizontal branch. I - Observations in the (log g, log T/eff/)-diagram

Log T(eff) and log g have been determined for blue horizontal branch (HB) stars in the globular clusters M15, M3, M5, M92, and NGC 288 as a first step in determining the physical origin of gaps or bimodal distributions in the blue horizontal branches of a number of globular clusters. The (log g, log T/eff/) diagram for the 'normal' HB cluster M5 matches the standard theory quite well. The stars blueward of the gap in NGC 288 and the blue extension of the M3 HB have significantly lower gravity than predicted by the standard theory. The cooler stars in M3 agree well with the standard theory while those of NGC 2988 lie at slightly lower gravity. In M92, the sequence of stars is broadened toward the low gravity side more than expected either from standard evolution or from observational error. The data for M15 are too scattered to support firm conclusions but seem consistent with NGC 288.

Crocker, Deborah A.↗

NASA NTRS1989

Measurements of vertical motions by the Saskatoon MF radar (1983-1985): Relationships with horizontal winds and gravity waves

The continuing series of horizontal wind measurements by the spaced-antenna real time winds (RTW) method was supplemented by a phase coherent system for two years. Vertical motions are inferred from the complex autocorrelation functions, and an RTW system provides 5 min samples from 60 to 110 km. Comparisons with full interferometric 3-D velocity measurements confirm the validity of this approach. Following comparisons and corrections with the horizontal winds, mean summer and winter (24 h) days of vertical motions are shown. Tidal fluctuations are evident. In summer the motions are downward, consistent with data from Poker Flat, and the suggestion of Coy et al. (1986) that these represent Eulerian motions. The expected upward Lagrangian motion then results from adding up upward Stokes' drift. The winter motions are more complex, and are discussed in the context of gravity wave fluxes and possible meridional cells. The divergence of the vertical flux of zonal momentum is also calculated and found to be similar to the coriolis torque due to the meridional winds.

Manson, A. H.↗

NASA NTRS1988

Horizontal plasma flow velocities in the ionosphere of Mars - A test case for the solar wind interaction

On the apparently nonmagnetic planets Mars and Venus, ionospheric plasma can be driven from the day to the nightside by two different mechanisms: (1) the pressure gradient force across the terminator, and (2) a solar wind-induced force via a viscous boundary layer interaction. Calculations of the horizontal flow velocities in the ionosphere of Mars using the two mechanisms produce results differing by an order of magnitude. It is pointed out that the detailed observations of the horizontal flow velocity in the ionosphere of Mars may provide a test case for the resolution of some problems relating to the interaction of the solar wind with the planets Mars and Venus.

Singhal, R. P.↗

NASA NTRS1989

Normal mode energetics and error analysis of GLA GCM simulations with different horizontal resolutions during a winter month

Comparative energetics is presented for a series of four general circulation model simulations for January 1979 conducted by the Goddard Laboratory for Atmospheres. The simulations include cases of coarse and fine horizontal model resolutions with two slightly different initial conditions. Using a three-dimensional normal mode expansion, it is found that the gravity-mode energy levels are significantly reduced in the higher wavenumbers and in the higher-order internal vertical modes by the increase of horizontal model resolution.

Tanaka, H. L.↗

NASA NTRS1989

Propagating and nonpropagating compression waves in an isothermal atmosphere with uniform horizontal magnetic field

Full analytical solutions to the wave equations for steady vertical compression waves in an isothermal hydrostatic atmosphere with a uniform horizontal magnetic field are presented. It is shown that, in the steady state approach, the behavior of upward waves and downward waves is very different. It is shown that the finding of Thomas (1983), indicating that the cutoff frequency for vertically propagating magnetoacoustic waves in an isothermal atmosphere with a horizontal magnetic field is the same for isothermal atmosphere with no magnetic field, is true only for the downward waves.

Musielak, Z. E.↗

NASA NTRS1990

Validation of a computer code for analysis of subsonic aerodynamic performance of wings with flaps in combination with a canard or horizontal tail and an application to optimization

Extensive correlations of computer code results with experimental data are employed to illustrate the use of a linearized theory, attached flow method for the estimation and optimization of the longitudinal aerodynamic performance of wing-canard and wing-horizontal tail configurations which may employ simple hinged flap systems. Use of an attached flow method is based on the premise that high levels of aerodynamic efficiency require a flow that is as nearly attached as circumstances permit. The results indicate that linearized theory, attached flow, computer code methods (modified to include estimated attainable leading-edge thrust and an approximate representation of vortex forces) provide a rational basis for the estimation and optimization of aerodynamic performance at subsonic speeds below the drag rise Mach number. Generally, good prediction of aerodynamic performance, as measured by the suction parameter, can be expected for near optimum combinations of canard or horizontal tail incidence and leading- and trailing-edge flap deflections at a given lift coefficient (conditions which tend to produce a predominantly attached flow).

Carlson, Harry W.↗

NASA NTRS1990

A computer module used to calculate the horizontal control surface size of a conceptual aircraft design

The creation of a computer module used to calculate the size of the horizontal control surfaces of a conceptual aircraft design is discussed. The control surface size is determined by first calculating the size needed to rotate the aircraft during takeoff, and, second, by determining if the calculated size is large enough to maintain stability of the aircraft throughout any specified mission. The tail size needed to rotate during takeoff is calculated from a summation of forces about the main landing gear of the aircraft. The stability of the aircraft is determined from a summation of forces about the center of gravity during different phases of the aircraft's flight. Included in the horizontal control surface analysis are: downwash effects on an aft tail, upwash effects on a forward canard, and effects due to flight in close proximity to the ground. Comparisons of production aircraft with numerical models show good accuracy for control surface sizing. A modified canard design verified the accuracy of the module for canard configurations. Added to this stability and control module is a subroutine that determines one of the three design variables, for a stable vectored thrust aircraft. These include forward thrust nozzle position, aft thrust nozzle angle, and forward thrust split.

Sandlin, Doral R.↗

NASA NTRS1990

FIRE aircraft observations of horizontal and vertical transport in marine stratocumulus

A major goal of research on marine stratocumulus is to try to understand the processes that generate and dissipate them. One approach to studying this problem is to investigate the boundary layer structure in the vicinity of a transition from a cloudy to a cloud-free region to document the differences in structure on each side of the transition. Since stratiform clouds have a major impact on the radiation divergence in the boundary layer, the transition from a cloudy to a clear boundary layer is a region of large horizontal inhomogeneity in air temperature and turbulence intensity. This leads to a considerable difference in horizontal and vertical transports between the cloudy and cloud-free regions. Measurements are used from the NCAR Electra aircraft during flights 5 (7 July 1987) and 10 (18 July 1987) of FIRE for this purpose. Flight 5 coincided with a LANDSAT overflight, and was designed to investigate the transition across a well-defined N-S cloud boundary, since the LANDSAT image can document the cloud cover in considerable detail. Turbulence legs were flown about 60 km on both sides of the cloud boundary. Flight 10 was flown at night in an area of scattered small cumuli and broken cloud patches.

Paluch, Ilga R.↗

NASA NTRS1990

Joint US/USSR study: Comparison of effects of horizontal and head-down bed rest

An account is given of the results of the first joint U.S./U.S.S.R. bed rest study. The study was accomplished in two parts: A soviet part (May to June 1979) and an American part (July to August 1979). Both studies were conducted under identical conditions and provided a basis for comparison of physiologic reactions and standardizing procedures and methods. Each experiment consisted of three periods: 14 days of pre-bed rest control, 7 days of bed rest, and a 10 to 14 day recovery period. Ten males participated in each study, with five subjects experiencing horizontal bed rest and five subjects a -6 deg head-down body position. Biochemical and hormonal measurements were made of blood and urine, with particular attention to electrolyte metabolism and kidney function; cardio-pulmonary changes at rest and exercise; influence of Lower Body Negative Pressure (LBNP); and incremental exercise using a bicyle ergometer while supine and sitting. Expected moderate changes were noted to occur for various physiologic parameters. Clinical evidence pointed to the fact that head-down bed rest when compared to horizontal conditions more closely matched the conditions seen after manned spaceflight. For the most part, statistically significant differences between the two body positions were not observed.

Sandler, Harold↗

NASA NTRS1990

The evolution of horizontal-branch stars - Theoretical sequences

A new grid of standard (i.e., solar CNO/Fe, no core rotation, and including semiconvection) horizontal-branch evolutionary sequences are presented which extend the grid of Sweigart both by including the final phase of core helium exhaustion and by using a finer grid of compositions. These sequences were constructed specifically for the studies of the Sandage period-shift effect and the second parameter phenomenon among the Galactic globular clusters. The numerical results for the observable characteristics of the sequences are tabulated which can be directly used to synthesize the observed horizontal-branch distributions. The present computations suggest that the observed difference in period change of RR Lyrae stars in the globular clusters M3 and M15 could be attributed, at least in the mean, to stellar evolution.

Lee, Young-Wook↗

NASA NTRS1990

Visual-vestibular interaction in humans during earth-horizontal axis rotation

Visual-vestibular interaction using 60 percent constant velocity earth horizontal axis yaw rotation, simulating both the horizontal semicircular canals and the otolith organs, was measured in seven human subjects. Subjects were tested with their eyes open in the dark (EOD) while fixating upon a target rotating with them (FIX), and while observing stationary optokinetic stripes (VVR). Resulting nystagmus slow component velocity (SCV) was analyzed for EOD, FIX, and VVR conditions. It is concluded that the visual-vestibular interactions during EHA differ significantly from those during rotation about the vertical; specifically, there is a nonlinear interaction between linear acceleration and optokinetic nystagmus.

Wall, Conrad, III↗

NASA NTRS1989

Forced convection and flow boiling with and without enhancement devices for top-side-heated horizontal channels

The effect of enhancement devices on flow boiling heat transfer in coolant channels, which are heated either from the top side or uniformly was studied. Studies are completed of the variations in the local (axial and circumferential) and mean heat transfer coefficients in horizontal, top-heated coolant channels with smooth walls and internal heat transfer enhancement devices. The working fluid is freon-11. The objectives are to: (1) examine the variations in both the mean and local (axial and circumferential) heat transfer coefficients for a circular coolant channel with either smooth walls or with both a twisted tape and spiral finned walls; (2) examine the effect of channel diameter (and the length-to-diameter aspect ratio) variations for the smooth wall channel; and (3) develop and improved data reduction analysis. The case of the top-heated, horizontal flow channel with smooth wall (1.37 cm inside diameter, and 122 cm heated length) was completed. The data were reduced using a preliminary analysis based on the heated hydraulic diameter. Preliminary examination of the local heat transfer coefficient variations indicated that there are significant axial and circumferential variations. However, it appears that the circumferential variation is more significant than the axial ones. In some cases, the circumferential variations were as much as a factor of ten. The axial variations rarely exceeded a factor of three.

Boyd, Ronald D., Sr.↗

NASA NTRS1991

Computational dispersion properties of horizontal staggered grids for atmospheric and ocean models

The computational dispersion properties of horizontally and time-horizontally staggered grids utilizing corresponding centered-difference techniques for approximation of the adjustment, or gravity wave equations, are examined in terms of their group velocity characteristics. Results are acquired for oceanic and atmospheric models, the former being characterized by a much smaller Rossby radius of deformation. For all grids considered additional filtering is required to control and even eliminate waves with poor computational dispersion characteristics. Computational dispersion properties along with other computational characteristics and requirements give some guidance for an optimal selection of an appropriate grid for an ocean or atmospheric model.

Fox-Rabinovitz, Michael S.↗

NASA NTRS1991

Horizontal wind fluctuations in the stratosphere during large-scale cyclogenesis

The meteorological measurement system (MMS) on the U-2 aircraft measured pressure, temperature, and the horizontal wind during a cyclogenesis event over western United States on April 20, 1984. The mean horizontal wind in the stratosphere decreases monotonically with altitude. Superimposed on the mean stratospheric wind is a perturbation wind vector, which is an elliptically polarized wave with an amplitude of 4 to 10 m/s and a vertical wavelength of 2 to 3 km. The perturbation wind vector rotates anticyclonically (clockwise) with altitude and produces alternating advection in the plane of the aircraft flight path. This differential advection folds surfaces of constant tracer mixing ratio and contributes to the observed tracer laminar structures and inferred cross-jet transport.

Chan, K. R.↗

NASA NTRS1992

Improved Fluidized-Bed Reactor With Horizontal Staging

Design of fluidized-bed reactor containing multiple, horizontally arrayed stages offers advantages over present multistage fluidized bed reactors with horizontal, vertical, or slanted stacking. In new reactor, solids proceed from one stage to next by flow over weir. Design promotes conservation of energy and optimization of flows and residence times.

Sullivan, Thomas A.↗

NASA NTRS1991

Trim drag reduction concepts for horizontal takeoff single-stage-to-Orbit vehicles

The results of a study to investigate concepts for minimizing trim drag of horizontal takeoff single-stage-to-orbit (SSTO) vehicles are presented. A generic hypersonic airbreathing conical configuration was used as the subject aircraft. The investigation indicates that extreme forward migration of the aerodynamic center as the vehicle accelerates to orbital velocities causes severe aerodynamic instability and trim moments that must be counteracted. Adequate stability can be provided by active control of elevons and rudder, but use of elevons to produce trim moments results in excessive trim drag and fuel consumption. To alleviate this problem, two solution concepts are examined. Active control of the center of gravity (COG) location to track the aerodynamic center decreases trim moment requirements, reduces elevon deflections, and leads to significant fuel savings. Active control of the direction of the thrust vector produces required trim moments, reduces elevon deflections, and also results in significant fuel savings. It is concluded that the combination of active flight control to provide stabilization, (COG) position control to minimize trim moment requirements, and thrust vectoring to generate required trim moments has the potential to significantly reduce fuel consumption during ascent to orbit of horizontal takeoff SSTO vehicles.

Shaughnessy, John D.↗