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
Filter
  • Fluid Mechanics and Thermodynamics  (44)
  • 1945-1949  (44)
  • 1
    facet.materialart.
    Unknown
    A Simplified Theory of Porous Wall Cooling (1947)
    In:  Other Sources
    Details
    Publication Date: 2019-07-12
    Description: The rate of heat transfer between a fluid stream in turbulent flow and a smooth, solid wall is largely controlled by the relatively high resistance of the laminar sublayer next to the wall. Although this laminar layer ii extremely thin, heat can be transferred through it only by molecular diffusion. Hence the resistance of this layer is very much greater than for a layer the same thickness farther out in the stream where turbulent exchange is the controlling factor. The thickness of the laminar layer is difficult to define precisely, since there is a gradual transition to the turbulent flow outside, but for the usual scale of many engineering applications almost half the temperature difference between the fluid and the wall occurs in a layer of a few thousands of an inch in thickness. When the wall is made of porous material and a coolant gas is forced through the wall into the stream, it has been found that a very small flow rate of the coolant is remarkably effective in keeping the wall at a low temperature. The coolant flow rate required is such as to give an average velocity normal cooling wall of the order of 1 per cent of the main stream velocity. This flow rate is so low that clearly the injected gas must act as an insulator rather than as a normal coolant. Because of its relatively low velocity, the injected gas can have very little influence on heat convection or momentum transfer in the turbulent stream, and its effect must be confined to the laminar sublayer. The possible influence of the coolant flow on the thickness of the laminar layer will be discussed in Section V.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: JPL-PR-4-50
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 2
    facet.materialart.
    Unknown
    Two-Dimensional Motion of a Gas at Large Supersonic Velocities (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: A large number of papers have been devoted to the problem of integration of equations of two-dimensional steady nonvertical adiabatic motion of a gas. Most of these papers are based on the application of the hodograph method of S. A. Chaplygin in which the plane of the hodograph of the velocity is taken as the region of variation of the independent variables in the equations of motion; the equations become linear in this plane. The exact integration of these equations is, however, obtained in the form of infinite series containing hypergeometric functions. The obtaining of such solutions and their investigation involves extensive computations. As a result, methods have been developed for the approximate integration of the equations of motion first transformed to a linear form. S. A. Chaplygin first pointed out such an approximate method applicable to flows in which the Mach number does not exceed 0.4.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1239 , Prikladnaia Matematika I Mekhanika, Tom XI
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 3
    facet.materialart.
    Unknown
    A Class of De Laval Nozzles (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: A study is made herein of the irrotational adiabatic motion of a gas in the transition from subsonic to supersonic velocities. A shape of the de Laval nozzle is given, which transforms a homogeneous plane-parallel flow at large subsonic velocity into a supersonic flow without any shockwaves beyond the transition line from the subsonic to the supersonic regions of flow. The method of solution is based on integration near the transition line of the gas equations of motion in the form investigated by S. A. Christianovich.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1236 , Prikladnaia Matematika I Mekhanika, Tom XI
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    The Characteristics Method Applied to Stationary Two-Dimensional and Rotationally Symmetrical Gas Flows (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: By means of characteristics theory, formulas for the numerical treatment of stationary compressible supersonic flows for the two-dimensional and rotationally symmetrical cases have been obtained from their differential equations.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1211 , ZWB Forschungsbericht; Rept-1581
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unknown
    The Turbulent Flow in Diffusers of Small Divergence Angle (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: The turbulent flow in a conical diffuser represents the type of turbulent boundary layer with positive longitudinal pressure gradient. In contrast to the boundary layer problem, however, it is not necessary that the pressure distribution along the limits of the boundary layer(along the axis of the diffuser) be given, since this distribution can be obtained from the computation. This circumstance, together with the greater simplicity of the problem as a whole, provides a useful basis for the study of the extension of the results of semiempirical theories to the case of motion with a positive pressure gradient. In the first part of the paper,formulas are derived for the computation of the velocity and.pressure distributions in the turbulent flow along, and at right angles to, the axis of a diffuser of small cone angle. The problem is solved.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1137 , Central Aero-Hydrodynaical Institute Reports; Rept-462
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 6
    facet.materialart.
    Unknown
    Vibration Survey of Blades in 19XB Axial-Flow Compressor (1948)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: Strain gages were used to measure blade vibrations possibly causing failure in the 10-stage compressor of the 19XB jet-propulsion engine. The seventh and tenth stages were of great concern as a result of failures experienced by the manufacturer. Strain-gage records were obtained from all stages during acceleration, deceleration, and constant speed runs. Curves are presented herein showing the maximum allowable vibratory stress for a given speed, the change of the damping coefficient with the mounting of a strain gage at the base of the blade, the effect of rotor speed, on blade natural frequency, and the effect of the order of first bending-mode vibration on stress. It was found that for all stages the lower the order of vibration the higher the stress but no destructive vibrations were detected.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-SE8A28
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 7
    facet.materialart.
    Unknown
    Effect of Air-Flow Distribution and Total-Pressure Loss on Performance of One-Sixth Segment of Turbojet Combuster (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: An investigation has been conducted on a one-sixth segment of an annular turbojet combustor to determine the effects of modification in air-flow distribution and total-pressure loss on the performance of the segment. The performance features investigated during this series of determinations were the altitude operational limits and the temperature-rise efficiency. Altitude operational limits of the combustor segment, for the 19XB engine using the original combustor-basket design were approximately 38,000 feet at 17,000 rpm and 26,000 feet at 10,000 rpm. The altitude operational limits were approximately 50,000 feet at 17,000 rpm and 38,000 feet at 10,000 rpm for a combustor-basket design in which the air-passage area in the basket was redistributed so as to admit gradually no more than 20 percent of the air along the first half of the basket. In this case the total pressure loss through the combustor segment was not appreciably changed from the total-pressure loss for the original combustor basket design. Altitude operational limits of the combustor segment for the 19XB engine were above 52,000 feet at 17,000 rpm and were approximately 23,000 feet at 10,000 rpm for a combustor-basket design in which the distribution of the air-passage area in the basket was that of the original design but where the total-pressure loss was increased to 19 times the inlet reference kinetic pressure at an inlet-to-outlet density ratio of 2.4. The total-pressure loss for the original design was 14 times the inlet kinetic reference pressure at an inlet-to-outlet density ratio of 2.4.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-SE7K16
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 8
    facet.materialart.
    Unknown
    Heat Transfer from High-Temperature Surfaces to Fluids III - Correlation of Heat-Transfer Data for Air Flowing in Silicon Carbide Tube with Rounded Entrance, Inside Diameter of 3/4 Inch, and Effective Length of 12 Inches (1949)
    In:  CASI
    Details
    Publication Date: 2019-08-13
    Description: A heat-transfer investigation was conducted with air flowing through an electrically heated silicon carbide tube with a rounded entrance, an inside diameter of 3/4 inch, and effective heat-transfer length of 12 inches over a range of Reynolds numbers up to 300,000 and a range of average inside-tube-wall temperatures up to 2500 R. The highest corresponding local outside-tube-wall temperature was 3010 R.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA/RM-E9D12
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 9
    facet.materialart.
    Unknown
    Behavior of the Laminar Boundary Layer for Periodically Oscillating Pressure Variation (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: The calculation of the phenomena within the boundary layer of bodies immersed in a flow underwent a decisive development on the basis of L. Prandtl's trains of thought, stated more than forth years ago, and by numerous later treatises again and again touching upon them. The requirements of the steadily improving aerodynamics of airplanes have greatly increased with the passing of time and recently research became particularly interested in such phenomena in the boundary layer as are caused by small external disturbances. Experimental results suggest that, for instance, slight fluctuations in the free stream velocities as they occur in wind tunnels or slight wavelike deviations of outer wing contours from the prescribed smooth course as they originate due to construction inaccuracies may exert strong effects on the extent of the laminar boundary layer on the body and thus on the drag. The development of turbulence in the last part of the laminar portion of the boundary layer is, therefore, the main problem, the solution of which explains the behavior of the transition point of the boundary layer. A number of reports in literature deal with this problem,for instance, those of Tollmien, Schlichting, Dryden, and Pretsch. The following discussion of the behavior of the laminar boundary layer for periodically oscillating pressure variation also purports to make a contribution to that subject.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1228 , Ludwig Prandtl zum 70. Geburtstage, Schriften der Deutschen Akademie der Luftfahrtforschung, Publications of the Germany academy for Aviation Research; 247-255
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 10
    facet.materialart.
    Unknown
    Some Aerodynamic Relations for an Airfoil in Oblique Flow (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: Some aerodynamic relations are derived which exist between two infinitely long airfoils if one is in a straight flow and the other in oblique flow, and both present the same profile in the direction of flow.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1158 , Deutsche Luftfahrtforschung, Forschungsbericht; Rept-1497
    Format: application/pdf
    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...