ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Advanced measurement techniques, part 1 (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: In modern laminar flow flight and wind tunnel research, it is important to understand the specific cause(s) of laminar to turbulent boundary layer transition. Such information is crucial to the exploration of the limits of practical application of laminar flow for drag reduction on aircraft. The process of transition involves both the possible modes of disturbance growth, and the environmental conditioning of the instabilities by freestream or surface conditions. The possible modes of disturbance growth include viscous, inviscid, and modes which may bypass these natural ones. Theory provides information on the possible modes of disturbance amplification, but experimentation must be relied upon to determine which of those modes actually dominates the transition process in a given environment. The results to date of research on advanced devices and methods used for the study of transition phenomena in the subsonic and transonic flight and wind tunnel environments are presented.
    Keywords: AERODYNAMICS
    Type: Research in Natural Laminar Flow and Laminar-Flow Control, Part 2; p 317-340
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 2
    facet.materialart.
    Unknown
    Off-surface infrared flow visualization (1993)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A method for visualizing off-surface flows is provided. The method consists of releasing a gas with infrared absorbing and emitting characteristics into a fluid flow and imaging the flow with an infrared imaging system. This method allows for visualization of off-surface fluid flow in-flight. The novelty of this method is found in providing an apparatus for flow visualization which is contained within the aircraft so as not to disrupt the airflow around the aircraft, is effective at various speeds and altitudes, and is longer-lasting than previous methods of flow visualization.
    Keywords: OPTICS
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 3
    facet.materialart.
    Unknown
    In-flight off-surface flow visualization using infrared imaging (1991)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A light test investigation was conducted to evaluate an infrared (IR) imaging technique to visualize off-surface flow phenomena. A single-engine, general-aviation airplane was equipped with an IR imaging system that viewed the region around the left wingtip. Vortical flow at the wingtip was seeded with surfur hexafluoride, a gas with strong infrared absorbing and emitting characteristics. Different terrain and sky backgrounds were evaluated for their effect on IR images of vortical flow. The best IR images were obtained with a clear background. The results of the investigation indicate that IR flow visualization compliments existing smoke generator methods for off-surface flow visualization.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Type: SAE PAPER 911006
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    Low-speed aerodynamic characteristics of a twin-engine general aviation configuration with aft-fuselage-mounted pusher propellers (1987)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An investigation was conducted to determine the aerodynamic characteristics of an advanced turboprop aircraft model with aft-pylon-mounted pusher propellers. Tests were conducted through an angle-of-attack range of -8 to 28 degrees, and an angle-of-sideslip range of -20 to 20 degrees at free-stream conditions corresponding to Reynolds numbers of 0.55 to 2.14 x 10 to the 6th power based on mean aerodynamic chord. Test results show that for the unpowered configurations the maximum lift coefficients for the cruise, takeoff, and landing configurations are 1.45, 1.90, and 2.10, respectively. Nacelle installation results in a drag coefficient increase of 0.01. Increasing propeller thrust results in a significant increase in lift for angles of attack above stall and improves the longitudinal stability. The cruise configuration remains longitudinally stable to an angle of attack 5 degrees beyond the stall angle, the takeoff configuration is stable 4 degrees beyond stall angle, and the landing configuration is stable 3 degrees beyond stall angle. The predominant effect of symmetric thrust on the lateral-directional aerodynamic characteristics is in the post-stall region, where additional rudder control is available with power on.
    Keywords: AERODYNAMICS
    Type: NASA-TP-2763 , L-16331 , NAS 1.60:2763
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unknown
    In-flight detection of Tollmien-Schlichting instabilities in laminar flow (1987)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: This paper presents the results of a recent flight experiment conducted to evaluate surface-mounted hot-film sensors designed to detect Tollmien-Schlichting instability in the boundary layer in flight. Flight data are presented to illustrate the design and operation of the sensors and to provide information on disturbance growth and transition mode. The results of calculations using a boundary-layer analysis code and boundary-layer linear stability analysis methods are included.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: SAE PAPER 871016
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 6
    facet.materialart.
    Unknown
    A New Method for Laminar Boundary Layer Transition Visualization in Flight: Color Changes in Liquid Crystal Coatings (1986)
    In:  CASI
    Details
    Publication Date: 2019-10-31
    Description: The visualization of laminar to turbulent boundary layer transition plays an important role in flight and wind tunnel aerodynamic testing of aircraft wing and body surfaces. Visualization can help provide a more complete understanding of both transition location as well as transition modes; without visualization, the transition process can be very difficult to understand. In the past, the most valuable transition visualization methods for fight applications included sublimating chemicals and oil flows. Each method has advantages and limitations. In particular, sublimating chemicals are impractical to use in subsonic applications much above 20,000 feet because of the greatly reduced rates of sublimation at lower temperatures (less than -4 degrees Fahrenheit). Both oil flow and sublimating chemicals have the disadvantage of providing only one good data point per flight. Thus, for many important flight conditions, transition visualization has not been readily available. This paper discusses a new method for visualizing transition in fight by the use of liquid crystals. The new method overcomes the limitations of past techniques, and provides transition visualization capability throughout almost the entire altitude and speed ranges of virtually all subsonic aircraft flight envelopes. The method also has wide applicability for supersonic transition visualization in flight and for general use in wind tunnel research over wide subsonic and supersonic speed ranges.
    Keywords: Aerodynamics
    Type: NASA-TM-87666 , NAS 1.15:87666
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 7
    facet.materialart.
    Unknown
    Developments in flow visualization methods for flight research (1990)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: With the introduction of modern airplanes utilizing laminar flow, flow visualization has become an important diagnostic tool in determining aerodynamic characteristics such as surface flow direction and boundary-layer state. A refinement of the sublimating chemical technique has been developed to define both the boundary-layer transition location and the transition mode. In response to the need for flow visualization at subsonic and transonic speeds and altitudes above 20,000 feet, the liquid crystal technique has been developed. A third flow visualization technique that has been used is infrared imaging, which offers non-intrusive testing over a wide range of test conditions. A review of these flow visualization methods and recent flight results is presented for a variety of modern aircraft and flight conditions.
    Keywords: AIRCRAFT INSTRUMENTATION
    Type: International Symposium; Aug 21, 1989 - Aug 25, 1989; Prague; Czechoslovakia
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 8
    facet.materialart.
    Unknown
    Infrared Imaging Of Flows Seeded With SF6 (1993)
    In:  Other Sources
    Details
    Publication Date: 2019-07-12
    Description: Novel technique enables repeated measurements of flow patterns during flight. Wing-tip vorticity studied in flight by observing infrared emissions from SF6 gas entrained in wing-tip flow. System makes vortical flows visible throughout all altitude and speed ranges of all subsonic aircraft. Also useful for transonic and supersonic speeds. Primary application is testing of aircraft in flight, also proves useful in testing fast land vehicles and structures or devices subject to strong winds.
    Keywords: PHYSICAL SCIENCES
    Type: LAR-14568 , NASA Tech Briefs (ISSN 0145-319X); 17; 6; P. 34
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 9
    facet.materialart.
    Unknown
    Measuring Tollmien-Schlichting Instabilities In Laminar Flow (1993)
    In:  Other Sources
    Details
    Publication Date: 2019-07-12
    Description: NASA flight experiment conducted to evaluate surface-mounted hot-film sensors designed to detect Tollmien-Schlichting (T-S) instability in boundary layer in flight. New technique has considerable value in applied research aimed at extending regions of natural laminar flow on aircraft. Aids research into mechanisms leading to transition from laminar to turbulent boundary layers. Makes it practical to take measurements in many locations on wing surface for tests in flight. Useful in studying transitions in such flow as those in pipes, ducts, channels, compressors, and diffusers.
    Keywords: MECHANICS
    Type: LAR-14132 , NASA Tech Briefs (ISSN 0145-319X); 17; 1; P. 73
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 10
    facet.materialart.
    Unknown
    Laminar-Separation Sensor (1988)
    In:  Other Sources
    Details
    Publication Date: 2019-07-12
    Description: Sensor detects flow reversal in boundary layer. Laminar-separation sensor provides means for detecting laminar-separation bubble by use of very thin, surface-mounted sensor. Consists of flush array of three proximate thin films. Middle film electronically heated by means of constant-temperature anemometer (CTA). Outer films, one upstream and one downstream of middle film, incorporated into bridge circuit to respond as resistance thermometers. This sensor provides only known surface-mounted means for positively identifying pressure of laminar separation as cause of boundary-layer transition.
    Keywords: MECHANICS
    Type: LAR-13463 , NASA Tech Briefs (ISSN 0145-319X); 12; 8; P. 72
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...