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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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Development and operation of a real-time simulation at the NASA Ames Vertical Motion Simulator

The Vertical Motion Simulator (VMS) facility at the NASA Ames Research Center combines the largest vertical motion capability in the world with a flexible real-time operating system allowing research to be conducted quickly and effectively. Due to the diverse nature of the aircraft simulated and the large number of simulations conducted annually, the challenge for the simulation engineer is to develop an accurate real-time simulation in a timely, efficient manner. The SimLab facility and the software tools necessary for an operating simulation will be discussed. Subsequent sections will describe the development process through operation of the simulation; this includes acceptance of the model, validation, integration and production phases.

Sweeney, Christopher↗
NASA NTRS1981

Simulator certification methods and the vertical motion simulator

The vertical motion simulator (VMS) is designed to simulate a variety of experimental helicopter and STOL/VTOL aircraft as well as other kinds of aircraft with special pitch and Z axis characteristics. The VMS includes a large motion base with extensive vertical and lateral travel capabilities, a computer generated image visual system, and a high speed CDC 7600 computer system, which performs aero model calculations. Guidelines on how to measure and evaluate VMS performance were developed. A survey of simulation users was conducted to ascertain they evaluated and certified simulators for use. The results are presented.

Showalter, T. W.↗
NASA NTRS2005

Feasibility of Measuring Mean Vertical Motion for Estimating Advection

Numerous recent studies calculate horizontal and vertical advection terms for budget studies of net ecosystem exchange of carbon. One potential uncertainty in such studies is the estimate of mean vertical motion. This work addresses the reliability of vertical advection estimates by contrasting the vertical motion obtained from the standard practise of measuring the vertical velocity and applying a tilt correction, to the vertical motion calculated from measurements of the horizontal divergence of the flow using a network of towers. Results are compared for three different tilt correction methods. Estimates of mean vertical motion are sensitive to the choice of tilt correction method. The short-term mean (10 to 60 minutes) vertical motion based on the horizontal divergence is more realistic compared to the estimates derived from the standard practise. The divergence shows long-term mean (days to months) sinking motion at the site, apparently due to the surface roughness change. Because all the tilt correction methods rely on the assumption that the long-term mean vertical motion is zero for a given wind direction, they fail to reproduce the vertical motion based on the divergence.

Vickers, Dean↗
NASA NTRS1993

Vertical motion simulator familiarization guide

The Vertical Motion Simulator Familiarization Guide provides a synoptic description of the Vertical Motion Simulator (VMS) and descriptions of the various simulation components and systems. The intended audience is the community of scientists and engineers who employ the VMS for research and development. The concept of a research simulator system is introduced and the building block nature of the VMS is emphasized. Individual sections describe all the hardware elements in terms of general properties and capabilities. Also included are an example of a typical VMS simulation which graphically illustrates the composition of the system and shows the signal flow among the elements and a glossary of specialized terms, abbreviations, and acronyms.

Danek, George L.↗
NASA NTRS1988

The relationship between large-scale vertical motion, highly reflective cloud, and sea surface temperature in the tropical Pacific region

Vertical motion fields at 850 mbar over the tropical Pacific region are calculated from the 1963-1973 mean wind fields for 4 months of the year and for October 1972, the peak month in the 1972-1973 El Nino event. These vertical motion fields are derived using the projective separation technique, which has the unique property of separating vertical motion into components due to meridional wind convergence and zonal wind convergence. This separation permits investigation of the response of the Hadley and Walker circulations to annual and interannual variation of the sea surface temperature in the tropical Pacific. The large-scale features of the computed vertical motion fields are in agreement with those of highly reflective clouds, which indicate the locations of deep convection. Examination of the annual cycle of the vertical motion and its components shows no strong variation of the Walker circulation with the east-west gradient of sea surface temperature. On the other hand, a strong correlation is found between meridional overturning in the eastern Pacific and the local equatorial sea surface temperature: during El Nino events, the eastern and central Pacific contribution to the Hadley circulation tends to increase.

Zimmermann, Peter H.↗
NASA NTRS1973

Vertical motion requirements for landing simulation

Tests were conducted to determine the significance of vertical acceleration cues in the simulation of the visual approach and landing maneuver. Landing performance measures were obtained for four subject pilots operating a visual landing simulation device which provides up to plus or minus 40 feet of vertical motion. Test results indicate that vertical motion cues are utilized in the landing task, and that they are particularly important in the simulation of aircraft with marginal longitudinal handling qualities. To assure vertical motion cues of the desired fidelity in the landing tasks, it appears that a simulator must have excursion capabilities of at least plus or minus 20 feet.

Bray, R. S.↗
NASA NTRS1973

A study of vertical motion requirements for landing simulation

Tests were conducted to determine the significance of vertical acceleration cues in the simulation of the visual approach and landing maneuver. Landing performance measures were obtained for four subject pilots operating a visual landing simulation mechanized in the Ames Height Control Test Apparatus, a device that provides up to plus or minus 40 ft of vertical motion. Test results indicate that vertical motion cues are utilized in the landing task, and that they are particularly important in the simulation of aircraft with marginal longitudinal-handling qualities. To assure vertical motion cues of the desired fidelity in the landing task, it appears, that a simulator must have excursion capabilities of at least 20 ft in either direction.

Bray, R. S.↗
NASA NTRS1988

Vertical motion as inferred by the VAS 6.7 micron water vapor channel

The change of topography of the upper-most water vapor layer is used as a tracer to directly estimate vertical motion in subtropical atmospheres. An equation for vertical motion is derived using the relationship between 6.7-micron brightness temperature and the altitude of the upper layer of water vapor. This equation is used to estimate the vertical motion over the southeastern U.S. for July, 1984. The obtained values are compared to the vertical motion derived kinematically from radiosondes.

Stout, John↗
NASA NTRS1979

Vertical motions in the equatorial middle atmosphere

A single station vertical velocity equation which considers ageostrophic and diabatic effects derived from the first law of thermodynamics and a generalized thermal wind relation is presented. An analysis and verification procedure which accounts for measurement and calculation errors as well as time and space continuity arguments and theoretical predictions are described. Vertical velocities are calculated at every kilometer between 25 and 60 km and for approximately every three hours for the above diurnal period at Kourou (French Guiana), Fort Sherman (Panama Canal Zone), Ascension Island, Antigua (British West Indies) and Natal (Brazil). The results, plotted as time series cross sections, suggest vertical motions ranging in magnitude from 1 or 2 cm/sec at 30 km to as much as 15 cm/sec at 60 km. Many of the general features of the results agree well with atmospheric tidal predictions but many particular features suggest that both smaller time scale gravity waves (periods less than 6 hours) and synoptic type waves (periods greater than 1 day) may be interacting significantly with the tidal fields. The results suggest that vertical motions can be calculated for the equatorial middle atmosphere and must be considered a significant part of the motion for time scales from 8 to 24 hours.

Weisman, M. L.↗
NASA NTRS1982

A comparison of adiabatic and kinematic vertical motions using mesoscale data

Results are compared from the adiabatic and kinematic methods of determining vertical motion during a period of severe convective storms when special meso alpha-scale rawinsonde data were available. The two procedures were tested using data from the first regional-scale day of AVE-SESAME '79 which coincided with the Red River Valley tornado outbreak of April 10-11, 1979. At 700 mb, each technique showed good agreement with the weather patterns, but the kinematic procedure gave superior results at 500 mb. The overall goodness of the adiabatic method during this particular case was not solely due to the high-resolution SESAME data since synoptic-scale mechanisms played a major role in creating a storm-conducive environment. With the advent of computer aided analysis systems such as AFOS, forecasters will have quicker access to a greater variety of information. Present results suggest that the adiabatic method can yield useful information for severe storm forecasters, especially in the lower troposphere. An interesting follow-on study would use sounding data from geostationary VAS satellites to compute adiabatic vertical motions at finer time and space resolutions than is now possible using RAOB data alone. Geostrophic winds derived from satellite thermal data probably can be used.

Fuelberg, H. E.↗
DOE OSTI2023

Incorporating the Effect of Large‐Scale Vertical Motion on Convection Through Convective Mass Flux Adjustment in E3SMv2

Abstract Recent observational studies suggest that the large‐scale dynamical forcing (vertical motion) plays important roles in deep convection development. In this study we propose a convective mass flux adjustment (MAdj) approach to represent the dynamical effects of large‐scale vertical motion on convection in the Department of Energy's Energy Exascale Earth System Model version 2 (E3SMv2). With MAdj, convection is enhanced (suppressed) when there is large‐scale ascending (descending) motion at the planetary boundary layer top. The coupling of convection with large‐scale circulation significantly improves the simulation of climate variability in E3SMv2 across multiple scales from the diurnal cycle, convectively coupled equatorial waves, to the Madden‐Julian Oscillation (MJO). The standard E3SMv2 tends to simulate overly weak diurnal amplitude of precipitation and overly weak variance of convectively coupled equatorial Kelvin and westward inertio‐gravity (WIG) waves. It also fails to simulate the essential characteristics of the MJO: continuous eastward propagation. With MAdj, the amplitude of diurnal cycle of precipitation is systematically increased and its probability density distribution is much closer to observations. The MAdj can also simulate more realistic eastward propagation of the MJO and much stronger convectively coupled Kelvin and WIG waves. Moreover, the MAdj approach slightly improves the climatology simulations in precipitation, cloud, radiation, circulation, temperature, and moisture fields, with overall root‐mean‐square error (RMSE) of major climatological fields reduced by about 2%. The MAdj approach suppresses excessive grid‐scale precipitation, reducing precipitation wet biases over South China Sea, Philippine Sea, Himalayas, and South Pacific Convergence Zone in western Pacific in summer.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1987

Diagnosis of vertical motion from VAS retrievals

Satellite-derived temperature profiles are used to determine if reliable estimates of synoptic-scale vertical motion can be obtained from the adiabatic, vorticity, and omega equation techniques. The period of study contains a short-wave trough over the Midwest and a convective outbreak over the middle Mississippi River Valley. Satellite soundings are available at 1-3 h intervals at five times. The emphasis is on assessing the strengths and weaknesses of the three vertical motion procedures, and determining the effects of short-interval observations on the calculations. Results show that the quasi-geostrophic omega equation provided patterns and magnitudes most consistent with observed weather events and 12 h radiosonde-derived motions. The vorticity method produced less satisfactory results, while adiabatic motions were unacceptable. The time derivative term dominated adiabatic motions and was a major influence in the vorticity method. Unrealistic temperature tendencies resulted from the retrieval algorithm; i.e., a diurnal temperature bias extended upwards to 500 mb, and there was a compensating effect at higher levels.

Fuelberg, Henry E.↗
NASA NTRS1980

Operations manual: Vertical Motion Simulator (VMS) S.08

The Ames Research Center Vertical Motion Simulator (VMS) is described in terms useful to the researcher who intends to use it. A description of the VMS and its performance are presented together with the administrative policies governing its operation. The management controls over its use are detailed, including data requirements, user responsibilities, and scheduling procedures. This information is given in a form that should facilitate communication with the NASA operations group during initial simulator use.

Jones, A. D.↗
NASA NTRS1990

Vertical motions in the Uranian atmosphere - An analysis of radio observations

The present, 6-cm radio map of Uranus indicates latitudinal features which may be due to vertical motions of the atmosphere. It appears in light of Voyager IR measurements as well as previously obtained radio data that these large-scale vertical motions, which have not undergone significant changes over the course of 8 years, extend from the 0.1- to the 45-bar levels; this span corresponds to a height of the order of 250 km. The latitudinal structures are believed to be primarily caused by horizontal variations of absorber abundances.

Hofstadter, Mark D.↗
NASA NTRS1984

The impact of latent heat release on synoptic-scale vertical motions and the development of an extratropical cyclone system

This study investigates the influence of stable and convective latent heat release on synoptic-scale vertical motions and the corresponding evolution of an extratropical cyclone during a 48 h period of strong development. The cyclone's early evolution was dominated by dry dynamical processes. By midway through the period, however, forcing by latent heat release accounted for over 50 percent of the upward vertical motions, with the convective component dominating. The cyclone's development was most intense during the second 24 h, despite a decrease in latent heat release. During the latter period, the reduced direct latent heat influence may have been augmented by an indirect influence, in which pre-existing dry dynamical forcing was enhanced by diabatic intensification of vorticity and thermal gradients.

Smith, P. J.↗