Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Visualization”

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 1,639 records · Page 91
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

High speed smoke flow visualization for the determination of cascade shock losses

A flow visualization technique has been developed by which quantitative cascade shock loss data can be ascertained without the interference effects of intrusive probes. The technique is first proven feasible by studying the high speed wind tunnel flow around a variety of two-dimensional shapes. Applicability is demonstrated by the testing of a 5% thick sharp-edged flat plate cascade at an upstream Mach number of about 1.3. Results are compared with the relevant theory and total pressure probe data.

Slovisky, J. A.↗
NASA NTRS1979

A visual investigation of the separation and subsequent transition near the leading edge of airfoils

Subsonic (5 to 30 m/sec) wind tunnels were used to measure pressure distributions at the leading edge and upper surface of airfoil models and to obtain high-speed movie photographs of smoke-visualized separation, transition, and reattachment phenomena. Points of turbulent shear layer reattachment could be determined by using an oil-mixture coating on the surface. Plots of the static pressure coefficient along the chord of several models are presented, and the measured separation, transition, and reattachment points are plotted against the chord Reynolds number.

Arena, A. V.↗
NASA NTRS1979

Qualitative and quantitative flow visualization technique using ozone

The paper describes a new flow-visualization technique based on the absorption of ultraviolet light by ozone. Ozone is an excellent tracer, because as a gas it has the same effective physical properties as air. Ozone strongly absorbs the principal line (253.7 nm) of a mercury lamp, so that when an ozone-traced flow passes between a mercury lamp and a fluorescent screen, a sharp, shadow-like image of the ozone tracer is cast on the screen. Quantitative photometry can be carried out by replacing the screen with ultraviolet detectors that yield the path-integrated column density of ozone in the flow. High-speed quantitative point monitoring (10 Hz at 10 ppb O3) is possible with capillary probes and chemiluminescent analysis.

Dickerson, R. R.↗
NASA NTRS1979

Wide-field electrographic cameras for imagery and spectrography at visual and middle-UV wavelengths

The use of a Kron electrographic detector for wide-field, narrow-band imagery of faint emission nebulosity in the near-UV and visual (3100-6000 A) wavelength interval is described. As an example of the photometric quality of the imagery and of the sensitivity of the instrumentation to diffuse, low-contrast objects, imagery of the Cygnus Loop supernova remnant in the high excitation forbidden line of Ne V 3426 A is presented. In addition, a program to develop electrographic detectors which use cesium telluride photocathodes for broad-band imagery and spectrography in the middle-UV (1650-3100 A) wavelength range is described.

Heckathorn, H. M.↗
NASA NTRS1979

Optical system of the visual imaging subsystem on the Viking Orbiter spacecraft

The development of the optical system for the Viking Orbiter spacecraft is presented. Each spacecraft consisted of an orbiter and a lander, and the orbiter provided support during the lander descent, landing and operation on the Martian surface, and prior to separation the orbiter provided science data for site selection and certification. To support these objectives each orbiter carried twin camera systems with identical 475 mm f/3.5 telescopes. The development of the Visual Imaging Subsystem which used all spherical catadioptric cassegrains with all elements fabricated from pure fused silica and Mangin primary mirrors is described. Computer aided design optimization and the ray aberration analysis of the final design are presented. The Viking telescopes had high theoretical and measured performance and obtained many high quality images of the Martian surface.

Larks, L.↗
NASA NTRS1979

Water tunnel visualization of the vortex flows of the F-15

Flow visualization studies were conducted in a diagnostic water tunnel to provide details of the wing, glove, and forebody vortex flow fields of the F-15 aircraft over a range of angles of attack and sideslip. Both the formation and breakdown of the vortex flow as a function of angle of attack and sideslip are detailed for the basic aircraft configuration. Additional tests showed that the wing upper surface vortex flows were sensitive to variations in an inlet mass flow ratio and an inlet cowl deflection angle. Two lengthened forebodies, one with a modified cross-sectional shape, were tested in addition to the basic forebody. Asymmetric forebody vortices were observed at zero sideslip and high angles of attack on each forebody. A large nose boom was added to each of the three forebodies, and it was observed that the turbulent wake shed from the boom disrupted the forebody vortices.

Lorincz, D. J.↗
NASA NTRS1979

Visual observations from space

Visual observations from space reveal a number of fascinating natural phenomena of interest to meteorologists and aeronomists, such as aurorae, airglow, aerosol layers, lightning, and atmospheric refraction effects. Other man-made radiation, including city lights and laser beacons, are also of considerable interest. Of course, the most widely used space observations are of the large-scale weather systems viewed each day by millions of people on their local television. From lower altitudes than the geostationary meteorological satellite orbits, obliques and overlapping stereo views are possible, allow height information to be obtained directly, often a key element in the use of the photographs for research purposes. However, this note will discuss only the less common observations mentioned at the beginning of this paragraph.

Garriott, O. K.↗
NASA NTRS1979

Test technique development in interference free testing, flow visualization, and remote control model technology at Langley's Unitary Plan wind tunnel

A metric half-span model is considered as a means of mechanical support for a wind-tunnel model which allows measurement of aerodynamic forces and moments without support interference or model distortion. This technique can be applied to interference-free propulsion models. The vapor screen method of flow visualization at supersonic Mach numbers is discussed. The use of smoke instead of water vapor as a medium to produce the screen is outlined. Vapor screen data are being used in the development of analytical vortex tracking programs. Test results for a remote control model system are evaluated. Detailed control effectiveness and cross-coupling data were obtained with a single run. For the afterbody tail configuration, tested control boundaries at several roll orientations were established utilizing the facility's on-line capability to 'fly' the model in the wind tunnel.

Corlett, W. A.↗
NASA NTRS1979

Visual observations over oceans

Important factors in locating, identifying, describing, and photographing ocean features from space are presented. On the basis of crew comments and other findings, the following recommendations can be made for Earth observations on Space Shuttle missions: (1) flyover exercises must include observations and photography of both temperate and tropical/subtropical waters; (2) sunglint must be included during some observations of ocean features; (3) imaging remote sensors should be used together with conventional photographic systems to document visual observations; (4) greater consideration must be given to scheduling earth observation targets likely to be obscured by clouds; and (5) an annotated photographic compilation of ocean features can be used as a training aid before the mission and as a reference book during space flight.

Terry, R. D.↗
NASA NTRS1979

Perception and performance in flight simulators: The contribution of vestibular, visual, and auditory information

The pilot's perception and performance in flight simulators is examined. The areas investigated include: vestibular stimulation, flight management and man cockpit information interfacing, and visual perception in flight simulation. The effects of higher levels of rotary acceleration on response time to constant acceleration, tracking performance, and thresholds for angular acceleration are examined. Areas of flight management examined are cockpit display of traffic information, work load, synthetic speech call outs during the landing phase of flight, perceptual factors in the use of a microwave landing system, automatic speech recognition, automation of aircraft operation, and total simulation of flight training.

Source record↗
NASA NTRS1980

Full scale visualization of the wing tip vortices generated by a typical agricultural aircraft

The trajectories of the wing tip vortices of a typical agricultural aircraft were experimentally determined by flight test. A flow visualization method, similar to the vapor screen method used in wind tunnels, was used to obtain trajectory data for a range of flight speeds, airplane configurations, and wing loadings. Detailed measurements of the spanwise surface pressure distribution were made for all test points. Further, a powered 1/8 scale model of the aircraft was designed, built, and used to obtain tip vortex trajectory data under conditions similar to that of the full scale test. The effects of light wind on the vortices were demonstrated, and the interaction of the flap vortex and the tip vortex was clearly shown in photographs and plotted trajectory data.

Cross, E. J., Jr.↗
NASA NTRS1980

Flow visualization techniques in the Airborne Laser Laboratory program

A turret/fairing assembly for laser applications was designed and tested. Wind tunnel testing was conducted using flow visualization techniques. The techniques used have included the methods of tufting, encapsulated liquid crystals, oil flow, sublimation and schlieren and shadowgraph photography. The results were directly applied to the design of fairing shapes for minimum drag and reduced turret buffet. In addition, the results are of primary importance to the study of light propagation paths in the near flow field of the turret cavity. Results indicate that the flow in the vicinity of the turret is an important factor for consideration in the design of suitable turret/fairing or aero-optic assemblies.

Walterick, R. E.↗
NASA NTRS1980

Plaid evaluation of visual access for PDP berthing and deployment

Tests were performed to evaluate visual access for berthing and deployment of the Plasma Diagnostic Package (PDP) in Space Transportation 4 Flight (STS-4). The Panel Layout Automated Interactive Design (PLAID), a 3 D computer graphics package, was used to construct models of the PDP, pallet, orbiter payload bay, the Remote Manipulator System (RMS), and other relevant elements to represent the STS-4 configuration. Several different assemblies were made, each one representing a snapshot of the PDP during berth/deploy maneuvers. Thirty-six views were produced during this test.

Brown, J. W.↗
NASA NTRS1980

Space shuttle orbiter flow visualization study

The vortex flows generated at subsonic speed during the final portion of atmospheric reentry were defined using a 0.01 scale model of the orbiter in a diagnostic water tunnel. Flow visualization photographs were obtained over an angle-of-attack range to 40 deg and sideslip angles up to 10 deg. The vortex flow field development, vortex path, and vortex breakdown characteristics were determined as a function of angle-of-attack at zero sideslip. Vortex flows were found to develop on the highly swept glove, on the wing, and on the upper surface of the fuselage. No significant asymmetries were observed at zero sideslip in the water tunnel tests. The sensitivity of the upper surface vortex flow fields to variations in sideslip angle was also studied. The vortex formed on the glove remained very stable in position above the wing up through the 10 deg of sideslip tested. There was a change in the vortex lifts under sideslip due to effective change in leading-edge sweep angles. Asymmetric flow separation occurred on the upper surface of the fuselage at small sideslip angles. The influence of vortex flow fields in sideslip on the lateral/ directional characteristics of the orbiter is discussed.

Lorincz, D. J.↗
NASA NTRS1980

Simulation and visualization of face seal motion stability by means of computer generated movies

A computer aided design method for mechanical face seals is described. Based on computer simulation, the actual motion of the flexibly mounted element of the seal can be visualized. This is achieved by solving the equations of motion of this element, calculating the displacements in its various degrees of freedom vs. time, and displaying the transient behavior in the form of a motion picture. Incorporating such a method in the design phase allows one to detect instabilities and to correct undesirable behavior of the seal. A theoretical background is presented. Details of the motion display technique are described, and the usefulness of the method is demonstrated by an example of a noncontacting conical face seal.

Etsion, I.↗
NASA NTRS1980

On the combination of kinematics with flow visualization to compute total circulation - Application to vortex rings in a tube

To date the computation of the total circulation, or strength of a vortex has required detailed measurements of the velocity field within the vortex. In this paper a method is described in which the kinematics of the vortical flow field is exploited to calculate the strength of a vortex from relatively simple flow visualization measurements. There are several advantages in the technique, the most important being the newly acquired ability to calculate the transient changes in strength of a single vortex as it evolves. The method is applied to the study of vortex rings, although the development can be carried over directly to study vortex pairs, and it is expected that it can be generalized to other flows which contain regions of concentrated vorticity. The accuracy of the method as applied to vortex rings, assessed in part by comparing with the laser Doppler velocimeter (LDV) measurements of Sullivan et al., is shown to be excellent.

Brasseur, J. G.↗