Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Translational”

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 703 records · Page 39
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Uncertainty in Synthetic Tropical Cyclone Hazard and Risk Estimates: Insights from RAFT, CHAZ, MIT, STORM, and CLIMADA

We synthesize five complementary tropical cyclone (TC) hazard frameworks—RAFT (physics-based machine learning), CHAZ and MIT (statistical–dynamical), STORM (fully statistical), and CLIMADA (observation-driven resampling)—to characterize uncertainty in wind-related TC metrics relevant to energy applications. All datasets and the IBTrACS observational record are harmonized to a common 6-hourly, 2.5° grid. We compare basin-wide and coastal properties using consistent definitions for TC frequency, mean and maximum intensity, 24-hour intensification, and 6-hour translation speed, and quantify agreement with Pearson r, RMSE, and Kling–Gupta efficiency (KGE) alongside resampling-based confidence intervals. CLIMADA is included for basin context but excluded from coastal skill scoring because it resamples historical IBTrACS; if supplied with projected future tracks from an external hazard model, CLIMADA can be used to simulate future TC scenarios. Results show robust, cross-model signals: (i) a corridor of activity from the tropical Atlantic through the Caribbean into the Bahamas and western subtropical Atlantic; (ii) a meridional dipole in 24-hour intensification (low-latitude strengthening, subtropical weakening); and (iii) a transition from slower tropical motion to faster midlatitude translation. Coastal winds (mean and maximum) consistently cluster from the eastern Gulf into the Bahamas–western Atlantic transition. The largest structural spread occurs in the amplitude and footprint of lifetime maximum intensity and, secondarily, in translation speed; intensification exhibits similar central behavior across frameworks with variability in extremes. Translation speed shows the most uniform coastal agreement. These findings provide a decision envelope for wind-focused risk screening and clarify where uncertainty should be carried forward; wind-only results represent a lower bound on total hazard, motivating integration of surge and rainfall modules and a companion, asset-level damage analysis.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2024

Dynamic performance of a passively self-adjusting floating wind farm layout to increase the annual energy production

One of the main differences between floating offshore wind turbines (FOWTs) and fixed-bottom turbines is the angular and translational motions of FOWTs. When it comes to planning a floating wind farm (FWF), the translational motions introduce an additional layer of complexity to the FWF layout. The ability of a FOWT to relocate its position represents an opportunity to mitigate wake losses within an FWF. By passively relocating downwind turbines out of the wake generated by upwind turbines, we can reduce wake-induced energy losses and enhance overall energy production. The translational movements of FOWTs are governed by the mooring system attached to it. The way a FOWT relocates its position changes if the design of the mooring system attached to it changes. Additionally, the translational motion of a FOWT attached to a given mooring system is different for different wind directions. Hence, we can tailor a mooring system design for a FOWT to passively control its motions according to the wind direction. In this work, we present a new self-adjusting FWF layout design and assess its performance using both static and dynamic methods. The results show that relocating the FOWTs in an FWF can increase the energy production by 3 % using a steady-state wake model and 1.4 % using a dynamic wake model at a wind speed of 10 m s -1 . Moreover, we compare the fatigue and ultimate loads of the mooring systems of the self-adjusting FWF layout design to the mooring systems in a current state-of-the-art FWF baseline design. The comparison shows that with smaller mooring system diameters, the self-adjusting FWF design has similar fatigue damage compared to the baseline design with bigger mooring system diameters at rated wind speed. Finally, the ultimate loads on the mooring systems of the self-adjusting FWF design are lower than those on the mooring systems of the baseline design.

17 WIND ENERGY↗
NASA NTRS1972

Aerodynamic and Acoustic Performance of Two Choked-Flow Inlets Under Static Conditions

Tests were conducted to determine the aerodynamic and acoustic performance of two choking flow inlets under static conditions. One inlet choked the flow in the cowl throat by an axial translation of the inlet centerbody. The other inlet employed a translating grid of airfoils to choke the flow. Both inlets were sized to fit a 13.97 cm diameter fan with a design weight flow of 2.49 kg/sec. The inlets were operated in both the choked and unchoked modes over a range of weight flows. Measurements were made of inlet pressure recovery, flow distortion, surface static pressure distribution, and fan noise suppression. Choking of the translating centerbody inlet reduced blade passing frequency noise by 29 db while yielding a total pressure recovery of 0.985. Noise reductions were also measured at 1/3-octave band center frequencies of 2500, 5000, and 20,000 cycles. The translating grid inlet gave a total pressure recovery of 0.968 when operating close to the choking weight flow. However, an intermittent high intensity noise source was encountered with this inlet that precluded an accurate measurement of inlet noise suppression.

Miller, B. A.↗
NASA NTRS1972

A precompiler for the formula manipulation system TRIGMAN.

Discussion of a translator designed to simplify the programming of problems involving the TRIGMAN formula manipulation system. The translator allows for the introduction of a new data type, SERIES, into a FORTRAN program and translates a user's program into legal FORTRAN. The translator is adaptable to other formula manipulation systems presently used in celestial mechanics.

Jefferys, W. H.↗
NASA NTRS1972

Study of astronaut restraints and mobility aids in a weightless shirtsleeve environment

A study, established to produce needed information about manual performance limits in intravehicular weightlessness such as the motions induced by the astronaut's direct application of force against the body of the vehicle or an object to be moved, is presented. Using both conventional and water immersion techniques, it was possible to develop realistic time estimates for astronaut station-to-station translation in Skylab, to simulate and analyze specific Skylab tasks involving force application and motion dynamics, and to evaluate certain thresholds of force application in weightlessness. The study was divided into three tasks. The first related to locomotion and verification or modification of present Skylab translation timelines. In all cases, translation times were less than the Skylab timelines indicated. The second task studied mass handling and transfer. Specifically, this involved measurement of the astronaut's ability to relocate the Skylab food lockers to stowage levels of three different heights and his ability to transfer the M509 PSS bottles between the OWS and the recharge station. The third task helped define the physical limits of man's ability to perform Skylab translation tasks under weightless conditions.

Loats, H. L., Jr.↗
NASA NTRS1976

Optical noise suppression device and method

A device and method is disclosed for suppression of optical noise in an optical spatial filtering system using highly coherent light. In the disclosed embodiment, input photographic film to be processed in the system, and output photographic film to be exposed, are each mounted on lateral translation devices. During application of the coherent light for exposure of the output film, the two translation devices are moved in synchronism by a motor-driven gear and linkage assembly. The ratio of the resulting output film translation to the input film translation is equal to the magnification of the optical data processing system. The noise pattern associated with the lenses and other elements in the optical processing system remains stationary while the image-producing light moves laterally through the pattern with the output film, thus averaging out the noise effect at the output film.

Horner, J. L.↗
NASA NTRS1989

Investigation of IGES for CAD/CAE data transfer

In a CAD/CAE facility there is always the possibility that one may want to transfer the design graphics database from the native system to a non-native system. This may occur because of dissimilar systems within an organization or a new CAD/CAE system is to be purchased. The Initial Graphics Exchange Specification (IGES) was developed in an attempt to solve this scenario. IGES is a neutral database format into which the CAD/CAE native database format can be translated to and from. Translating the native design database format to IGES requires a pre-processor and transling from IGES to the native database format requires a post-processor. IGES is an artifice to represent CAD/CAE product data in a neutral environment to allow interfacing applications, archive the database, interchange of product data between dissimilar CAD/CAE systems, and other applications. The intent here is to present test data on translating design product data from a CAD/CAE system to itself and to translate data initially prepared in IGES format to various native design formats. This information can be utilized in planning potential procurement and developing a design discipline within the CAD/CAE community.

Zobrist, George W.↗
NASA NTRS1991

Frame Shift/warp Compensation for the ARID Robot System

The Automatic Radiator Inspection Device (ARID) is a system aimed at automating the tedious task of inspecting orbiter radiator panels. The ARID must have the ability to aim a camera accurately at the desired inspection points, which are in the order of 13,000. The ideal inspection points are known; however, the panel may be relocated due to inaccurate parking and warpage. A method of determining the mathematical description of a translated as well as a warped surface by accurate measurement of only a few points on this surface is developed here. The method uses a linear warp model whose effect is superimposed on the rigid body translation. Due to the angles involved, small angle approximations are possible, which greatly reduces the computational complexity. Given an accurate linear warp model, all the desired translation and warp parameters can be obtained by knowledge of the ideal locations of four fiducial points and the corresponding measurements of these points on the actual radiator surface. The method uses three of the fiducials to define a plane and the fourth to define the warp. Given this information, it is possible to determine a transformation that will enable the ARID system to translate any desired inspection point on the ideal surface to its corresponding value on the actual surface.

Latino, Carl D.↗
NASA NTRS1993

Transforming AdaPT to Ada9x

How the concepts of AdaPT can be transformed into programs using the object oriented features proposed in the preliminary mapping for Ada9x are described. Emphasizing, as they do, the importance of data types as units of program, these features match well with the development of partitions as translations into Abstract Data Types which was exploited in the Ada83 translation covered in report R3. By providing a form of polymorphic type, the Ada83 version also gives support for the conformant partition idea which could be achieved in Ada83 only by using UNCHECKED CONVERSIONS. It is assumed that the reader understands AdaPT itself, but the translation into Ada83 is briefly reviewed, by applying it to a small example. This is then used to show how the same translation would be achieved in the 9x version. It is important to appreciate that the distribution features which are proposed in current mapping are not used or discussed in any detail, as those are not well matched to the AdaPT approach. Critical evaluation and comparison of these approaches is given in a separate report.

Goldsack, Stephen J.↗
NASA NTRS1992

EVA results of Shuttle Mission STS-37

The paper summarizes EVA results of the STS-37 mission that flew in April 1991, with emphasis on the unscheduled EVA to free the Compton GRO antenna. The EVA Development Flight Experiment (EDFE) objectives and equipment description are also presented. The EDFE consisted of three experiments conducted during STS-37 to evaluate both designs of crew translation equipment and loads imparted by crew members while performing typical EVA work site tasks for Space Station Freedom. The experiments were used to evaluate static and dynamic loads and ease of operation of four separate translation systems operating on a fixed track. Various measures of performance of the crew equipment and translation aids are discussed. The rates and accelerations experienced during translation aided by the manipulator foot restraint and remote manipulator system were found to be comfortable.

Whitsett, C. E.↗
NASA NTRS1993

Spline screw multiple rotations mechanism

A system for coupling two bodies together and for transmitting torque from one body to another with mechanical timing and sequencing is reported. The mechanical timing and sequencing is handled so that the following criteria are met: (1) the bodies are handled in a safe manner and nothing floats loose in space, (2) electrical connectors are engaged as long as possible so that the internal processes can be monitored throughout by sensors, and (3) electrical and mechanical power and signals are coupled. The first body has a splined driver for providing the input torque. The second body has a threaded drive member capable of rotation and limited translation. The embedded drive member will mate with and fasten to the splined driver. The second body has an embedded bevel gear member capable of rotation and limited translation. This bevel gear member is coaxial with the threaded drive member. A compression spring provides a preload on the rotating threaded member, and a thrust bearing is used for limiting the translation of the bevel gear member so that when the bevel gear member reaches the upward limit of its translation the two bodies are fully coupled and the bevel gear member then rotates due to the input torque transmitted from the splined driver through the threaded drive member to the bevel gear member. An output bevel gear with an attached output drive shaft is embedded in the second body and meshes with the threaded rotating bevel gear member to transmit the input torque to the output drive shaft.

Vranish, John M.↗
NASA NTRS1994

Theoretical studies of a molecular beam generator

We consider the problem of modeling a high temperature diatomic gas N2 flowing through a converging-diverging high expansion nozzle. The problem is modeled in two ways. The first model uses a single temperature with variable specific heats as functions of this temperature. For the second model we assume that the various degrees of freedom all have a Boltzmann population distribution which means that each degree of freedom has its own temperature and consequently each system state can be characterized by these temperatures. This suggests the formulation of a second model with a vibrational degree of freedom as having its own temperature along with a rotational-translational degree of freedom with its own temperature. Initially the vibrational degree of freedom is excited by heating the gas to a high temperature. As the high temperature gas expands through the nozzle throat there is a sudden drop in the rotational-translational temperature along with a finite relaxation time for the vibrational degree of freedom to achieve equilibrium with the rotational-translational degree of freedom. That is, the temperature change that occurs when the N2 gas passes through the nozzle throat is so great that the changes in the vibrational degree of freedom lags behind the rotational-translational energy changes. The resulting relaxation time is finite. It is in this context that the term nonequilibrium is used. That is, the term nonequilibrium denotes the fact that the energy content of the various degrees of freedom are characterized by two temperatures. We neglect any chemical reactions resulting from the high temperatures which could also add nonequilibrium effects. We develop the basic equations for the two models in various forms in order to check the derivations with other sources. The final form which is solved numerically consists of the scaled equations in a conservative dimensionless form.

Heinbockel, John H.↗
NASA NTRS1994

The study of dopant segregation behavior during the growth of GaAs in microgravity

An investigation into the segregation behavior of selenium doped gallium arsenide during directional solidification in the microgravity environment was conducted using the Crystal Growth Furnace (CGF) aboard the first United States Microgravity Laboratory (USML-1). The two crystals grown were 1.5 cm in diameter and 16.5 cm in length with an initial melt length of 14 cm. Two translation periods were executed, the first at 2.5 microns/s and after a specified time, which was different between the two experiments, the translation rate was doubled to 5.0 microns/s. The translation was then stopped and the remaining sample melt was solidified using a gradient freeze technique in the first sample and a rapid solidification in the second experiment. Measurement of the selenium dopant distribution, using quantitative infrared transmission imaging, indicates that the first sample initially achieved diffusion controlled growth as desired. However, after about 1 cm of growth, the segregation behavior was driven from a diffusion controlled growth regime to a complete mixing regime. Measurements in the second flight sample indicated that the growth was always in a complete mixing regime. In both experiments, voids in the center line of the crystal, indicative of bubble entrapment, were found to correlate with the position in the crystal when the translation rates were doubled.

Matthiesen, David H.↗
NASA NTRS1995

An overview of the Evaluation of Oxygen Interactions with Materials 3 experiment: Space Shuttle Mission 46, July-August 1992

The Evaluation of Oxygen Interactions with Materials 3 (EOIM-3) flight experiment was developed to obtain benchmark atomic oxygen reactivity data and was conducted during Space Transportation System Mission 46 (STS-46), July 31 to August 7, 1992. In this paper, we present an overview of EOIM-3 and the results of the Lyndon B. Johnson Space Center (JSC) materials reactivity and mass spectrometer/carousel experiments. Mass spectrometer calibration methods are discussed briefly, as a prelude to a detailed discussion of the mass spectrometric results produced during STS-46. Mass spectrometric measurements of ambient O-atom flux and fluence are in good agreement with the values calculated using the MSIS-86 model of the thermosphere as well as estimates based on the extent of O-atom reaction with Kapton polyimide. Mass spectrometric measurements of gaseous products formed by O-atom reaction with C(13) labeled Kapton revealed CO, CO2, H2O, NO, and NO2. Finally, by operating the mass spectrometer so as to detect naturally occurring ionospheric species, we characterized the ambient ionosphere at various times during EOIM-3 and detected the gaseous reaction products formed when ambient ions interacted with the C(13) Kapton carousel sector. By direct comparison of the results of on-orbit O-atom exposures with those conducted in ground-based laboratory systems, which provide known O-atom fluences and translational energies, we have demonstrated the strong translational energy dependence of O-atom reactions with a variety of polymers. A 'line-of-centers' reactive scattering model was shown to provide a reasonably accurate description of the translational energy dependence of polymer reactions with O atoms at high atom kinetic energies while a Beckerle-Ceyer model provided an accurate description of O-atom reactivity over a three order-of-magnitude range in translational energy and a four order-of-magnitude range in reaction efficiency. Postflight studies of the polymer samples by x-ray photoelectron spectroscopy and infrared spectroscopy demonstrate that O-atom attack is confined to the near-surface region of the sample, i.e. within 50 to 100 A of the surface.

Koontz, Steven L.↗
NASA NTRS1996

Flight evaluation of advanced controls and displays for transition and landing on the NASA V/STOL systems research aircraft

Flight experiments were conducted on Ames Research Center's V/STOL Systems Research Aircraft (VSRA) to assess the influence of advanced control modes and head-up displays (HUD's) on flying qualities for precision approach and landing operations. Evaluations were made for decelerating approaches to hover followed by a vertical landing and for slow landings for four control/display mode combinations: the basic YAV-8B stability augmentation system; attitude command for pitch, roll, and yaw; flightpath/acceleration command with translational rate command in the hover; and height-rate damping with translational-rate command. Head-up displays used in conjunction with these control modes provided flightpath tracking/pursuit guidance and deceleration commands for the decelerating approach and a mixed horizontal and vertical presentation for precision hover and landing. Flying qualities were established and control usage and bandwidth were documented for candidate control modes and displays for the approach and vertical landing. Minimally satisfactory bandwidths were determined for the translational-rate command system. Test pilot and engineer teams from the Naval Air Warfare Center, the Boeing Military Airplane Group, Lockheed Martin, McDonnell Douglas Aerospace, Northrop Grumman, Rolls-Royce, and the British Defense Research Agency participated in the program along with NASA research pilots from the Ames and Lewis Research Centers. The results, in conjunction with related ground-based simulation data, indicate that the flightpath/longitudinal acceleration command response type in conjunction with pursuit tracking and deceleration guidance on the HUD would be essential for operation to instrument minimums significantly lower than the minimums for the AV-8B. It would also be a superior mode for performing slow landings where precise control to an austere landing area such as a narrow road is demanded. The translational-rate command system would reduce pilot workload for demanding vertical landing tasks aboard ship and in confined land-based sites.

Franklin, James A.↗
NASA NTRS1997

Parallelization of Rocket Engine Simulator Software (PRESS)

Parallelization of Rocket Engine System Software (PRESS) project is part of a collaborative effort with Southern University at Baton Rouge (SUBR), University of West Florida (UWF), and Jackson State University (JSU). The second-year funding, which supports two graduate students enrolled in our new Master's program in Computer Science at Hampton University and the principal investigator, have been obtained for the period from October 19, 1996 through October 18, 1997. The key part of the interim report was new directions for the second year funding. This came about from discussions during Rocket Engine Numeric Simulator (RENS) project meeting in Pensacola on January 17-18, 1997. At that time, a software agreement between Hampton University and NASA Lewis Research Center had already been concluded. That agreement concerns off-NASA-site experimentation with PUMPDES/TURBDES software. Before this agreement, during the first year of the project, another large-scale FORTRAN-based software, Two-Dimensional Kinetics (TDK), was being used for translation to an object-oriented language and parallelization experiments. However, that package proved to be too complex and lacking sufficient documentation for effective translation effort to the object-oriented C + + source code. The focus, this time with better documented and more manageable PUMPDES/TURBDES package, was still on translation to C + + with design improvements. At the RENS Meeting, however, the new impetus for the RENS projects in general, and PRESS in particular, has shifted in two important ways. One was closer alignment with the work on Numerical Propulsion System Simulator (NPSS) through cooperation and collaboration with LERC ACLU organization. The other was to see whether and how NASA's various rocket design software can be run over local and intra nets without any radical efforts for redesign and translation into object-oriented source code. There were also suggestions that the Fortran based code be encapsulated in C + + code thereby facilitating reuse without undue development effort. The details are covered in the aforementioned section of the interim report filed on April 28, 1997.

Cezzar, Ruknet↗
NASA NTRS1998

Effect of Finite Computational Domain on Turbulence Scaling Law in Both Physical and Spectral Spaces

The well-known translation between the power law of energy spectrum and that of the correlation function or the second order structure function has been widely used in analyzing random data. Here, we show that the translation is valid only in proper scaling regimes. The regimes of valid translation are different for the correlation function and the structure function. Indeed, they do not overlap. Furthermore, in practice, the power laws exist only for a finite range of scales. We show that this finite range makes the translation inexact even in the proper scaling regime. The error depends on the scaling exponent. The current findings are applicable to data analysis in fluid turbulence and other stochastic systems.

Hou, Thomas Y.↗
NASA NTRS1999

Analysis of X-Ray Microradiographs of Al-Au Interface Quench Profile using Modeling of Solidification Including Double-Diffusion and Convection in the Melt

Experimental data on Al-0.8Au horizontal solidification of a 1 mm thick specimen in a BN crucible shows the effect of growth rate on the solidification interface shape. For translation rates below 0.5 micron/s the interface maintains a plain and flat shape. When the translation rate is 3 to 5 micron/s or more, the interface appearance changes to two planar zones, with the zone closer to the bottom having higher inclination. The interface shapes were measured by first quenching in place during growth. X-ray microscopy shows the interface shape within the quenched sample by viewing through the side of the specimen. In order to provide theoretical explanation of the phenomena, numerical modeling was undertaken using finite element code FIDAP. Double diffusion convection in Al-0.8Au melt and crystal-melt interface curvature during directional solidification was analyzed numerically. Actual thermophysical properties of Al-0.8Au including the binary Al-Au phase diagram were used. Although convection in the sample is weak, for the slower translation rate convection and diffusion is sufficient for the redistribution of initial compositional stratification caused by gravity. When translation rate is raised, neither convection nor diffusion can provide proper mixing so that solidification temperatures differ significantly near the bottom within the bulk of the sample. As a result, the solid-liquid interface appears to have two planar zones with different inclination.

Bune, Andris V.↗