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Measurements of free-space oscillating pressures near propellers at flight Mach numbers to 0.72 (open access)

Measurements of free-space oscillating pressures near propellers at flight Mach numbers to 0.72

"In the course of a short flight program initiated to check the theory of Garrick and Watkins (NACA rep. 1198), a series of measurements at three stations were made of the oscillating pressures near a tapered-blade plan-form propeller and rectangular-blade plan form propeller at flight Mach numbers up to 0.72. In contradiction to the results for the propeller studied in NACA rep. 1198, the oscillating pressures in the plane ahead of the propeller were found to be higher than those immediately behind the propeller. Factors such as variation in torque and thrust distribution, since the blades of the present investigation were operating above their design forward speed, may account for this contradiction" (p. 999).
Date: July 1, 1958
Creator: Kurbjun, Max C. & Vogeley, Arthur W.
System: The UNT Digital Library
The Compressible Laminar Boundary Layer with Heat Transfer and Arbitrary Pressure Gradient (open access)

The Compressible Laminar Boundary Layer with Heat Transfer and Arbitrary Pressure Gradient

"An approximate method for the calculation of the compressible laminar boundary layer with heat transfer and arbitrary pressure gradient, based on Thwaites' correlation concept, is presented. With the definition of dimensionless shear and heat-transfer parameters and an assumed correlation of these parameters in terms of a momentum parameter, a complete system of relations for calculating skin friction and heat transfer results. Knowledge of velocity or temperature profiles is not necessary in using this calculation method" (p. 1).
Date: February 1, 1955
Creator: Cohen, Clarence B. & Reshotko, Eli
System: The UNT Digital Library
Minimum-drag ducted and pointed bodies of revolution based on linearized supersonic theory (open access)

Minimum-drag ducted and pointed bodies of revolution based on linearized supersonic theory

The linearized drag integral for bodies of revolution at supersonic speeds is presented in a double-integral form which is not based on slender-body approximations but which reduces to the equal slender-body expression in the proper limit. With the aid of a suitably chosen auxiliary condition, the minimum-external-wave-drag problem is solved for a transition section connecting two semi-infinite cylinders. The projectile tip is a special case and is compared with the Von Karman projectile tip. Calculations are presented which indicate that the method of analysis gives good first-order results in the moderate supersonic range.
Date: March 1, 1954
Creator: Parker, Hermon M.
System: The UNT Digital Library
High-Resolution Autoradiography (open access)

High-Resolution Autoradiography

This investigation was made to adapt wet-process autoradiography to metallurgical samples to obtain high resolution of segregated radioactive elements in microstructures. Results are confined to development of the technique, which was perfected to a resolution of less than 10 microns. The radioactive samples included carbon-14 carburized iron and steel, nickel-63 electroplated samples, a powder product containing nickel-63, and tungsten-185 in N-155 alloy.
Date: June 1, 1953
Creator: Towe, George C.; Gomberg, Henry J. & Freemen, J. W.
System: The UNT Digital Library
Relation Between Roughness of Interface and Adherence of Porcelain Enamel to Steel (open access)

Relation Between Roughness of Interface and Adherence of Porcelain Enamel to Steel

"Porcelain-enamel ground coats were prepared and applied under conditions that gave various degrees of adherence between enamel and a low-carbon steel (enameling iron). The variations in adherence were produced by (a) varying the amount of cobalt-oxide addition in the frit, (b) varying the type of metallic-oxide addition in the frit, keeping the amount constant at 0.8 weight percent, (c) varying the surface treatment of the metal before application of the enamel, by pickling, sandblasting, and polishing, and (d) varying the time of firing of the enamel containing 0.8 percent of cobalt oxide. Specimens of each enamel were given the standard adherence test of the Porcelain Enamel Institute" (p. 239).
Date: October 1, 1952
Creator: Richmond, J. C.; Moore, D. G.; Kirkpatrick, H. B. & Harrison, W. N.
System: The UNT Digital Library
Mechanism of Start and Development of Aircraft Crash Fires (open access)

Mechanism of Start and Development of Aircraft Crash Fires

"Full-scale aircraft crashes were made to investigate the mechanism of the start and development of aircraft crash fires. The results are discussed herein. This investigation revealed the characteristics of the ignition sources, the manner in which the combustibles spread, the mechanism of the union of the combustibles and ignition sources, and the pertinent factors governing the development of a crash fire as observed in this program" (p. 547).
Date: August 1, 1952
Creator: Pinkel, I. Irving; Preston, G. Merritt & Pesman, Gerard J.
System: The UNT Digital Library
A study of the zero-lift drag-rise characteristics of wing-body combinations near the speed of sound (open access)

A study of the zero-lift drag-rise characteristics of wing-body combinations near the speed of sound

"Comparisons have been made of the shock phenomena and drag-rise increments for representative wing and central-body combinations with those for bodies of revolution having the same axial developments of cross-sectional areas normal to the airstream. On the basis of these comparisons, it is concluded that near the speed of sound the zero-lift drag rise of a low-aspect-ratio thin-wing and body combination is primarily dependent on the axial development of the cross-sectional areas normal to the airstream. It follows that the drag rise for any such configuration is approximately the same as that for any other with the same development of cross-sectional areas" (p. 519).
Date: August 1, 1952
Creator: Whitcomb, Richard T.
System: The UNT Digital Library
Theoretical study of the transonic lift of a double-wedge profile with detached bow wave (open access)

Theoretical study of the transonic lift of a double-wedge profile with detached bow wave

"A theoretical study is described of the aerodynamic characteristics at small angle of attack of a thin, double-wedge profile in the range of supersonic flight speed in which the bow wave is detached. The analysis is carried out within the framework of the transonic (nonlinear) small-disturbance theory, and the effects of angle of attack are regarded as a small perturbation on the flow previously calculated at zero angle. The mixed flow about the front half of the profile is calculated by relaxation solution of a suitably defined boundary-value problem for transonic small-disturbance equation in the hodograph plane (i.e., the Tricomi equation)" (p. 547).
Date: August 1, 1952
Creator: Vincenti, Walter G. & Wagoner, Cleo B.
System: The UNT Digital Library
Direct Measurements of Skin Friction (open access)

Direct Measurements of Skin Friction

"A device has been developed to measure local skin friction on a flat plate by measuring the force exerted upon a very small movable part of the surface of the flat plate. These forces, which range from about 1 milligram to about 100 milligrams, are measured by means of a reactance device. The apparatus was first applied to measurements in the low-speed range, both for laminar and turbulent boundary layers. The device was then applied to high-speed subsonic flow and the turbulent-skin-friction coefficients were determined up to a Mach number of about 0.8" (p. 281).
Date: June 1, 1951
Creator: Dhawan, Satish
System: The UNT Digital Library
Theoretical and Experimental Investigation of Additive Drag (open access)

Theoretical and Experimental Investigation of Additive Drag

"The significance of additive drag is discussed and equations for determining its approximate value are derived for annular and open-nose inlets. Charts are presented giving values of additive drag coefficient over a range of free-stream Mach numbers for open and for annular-nose inlets with conical flow at the inlet. The effects on additive drag of variable inlet-total-pressure recovery and static pressures on the centerbody are investigated and an analytical method of predicting the variation of pressure on the centerbody with mass-flow ratio is given" (p. 1).
Date: February 1, 1951
Creator: Sibulkin, Merwin
System: The UNT Digital Library
Generalization of Boundary-Layer Momentum-Integral Equations to Three-Dimensional Flows Including Those of Rotating System (open access)

Generalization of Boundary-Layer Momentum-Integral Equations to Three-Dimensional Flows Including Those of Rotating System

"The Navier-Stokes equations of motion and the equation of continuity are transformed so as to apply to an orthogonal curvilinear coordinate system rotating with a uniform angular velocity about an arbitrary axis in space. A usual simplification of these equations as consistent with the accepted boundary-layer theory and an integration of these equations through the boundary layer result in boundary-layer momentum-integral equations for three-dimensional flows that are applicable to either rotating or nonrotating fluid boundaries. These equations are simplified and an approximate solution in closed integral form is obtained for a generalized boundary-layer momentum-loss thickness and flow deflection at the wall in the turbulent case" (p. 1).
Date: November 1, 1950
Creator: Mager, Artur
System: The UNT Digital Library
Analysis of thrust augmentation of turbojet engines by water injection at compressor inlet including charts for calculating compression processes with water injection (open access)

Analysis of thrust augmentation of turbojet engines by water injection at compressor inlet including charts for calculating compression processes with water injection

From Summary: "Curves are presented that show the theoretical performance of the augmentation method for various amounts of water injected and the effects of varying flight Mach number, altitude, ambient-air temperature, ambient relative humidity, compressor pressure ratio, and inlet-diffuser efficiency. Numerical examples, illustrating the use of the psychrometric chart and the Mollier diagram in calculating both compressor-inlet and compressor-outlet conditions when water is injected at the compressor inlet, are presented."
Date: June 1, 1950
Creator: Wilcox, E. Clinton & Trout, Arthur M.
System: The UNT Digital Library
Analysis of spanwise temperature distribution in three types of air-cooled turbine blade (open access)

Analysis of spanwise temperature distribution in three types of air-cooled turbine blade

From Summary: An approximate method for determining the allowable stress-limited blade-temperature distribution is included, with brief accounts of a method for determining the maximum allowable effective gas temperatures and the cooling-air requirements. Numerical examples that illustrate the use of the various temperature-distribution equations and of the nondimensional charts are also included.
Date: March 1, 1950
Creator: Livingood, John N. B. & Brown, W. Byron
System: The UNT Digital Library
Method of designing cascade blades with prescribed velocity distributions in compressible potential flows (open access)

Method of designing cascade blades with prescribed velocity distributions in compressible potential flows

By use of the assumption that the pressure-volume relation is linear, a solution to the problem of designing a cascade for a given turning and with a prescribed velocity distribution along the blade in a potential flow of a compressible perfect fluid was obtained by a method of correspondence between potential flows of compressible and incompressible fluids. The designing of an isolated airfoil with a prescribed velocity distribution along the airfoil is considered as a special case of cascade. If the prescribed velocity distribution is not theoretically attainable, the method provides a means of modifying the distribution so as to obtain a physically significant blade shape. Numerical examples are included.
Date: October 1, 1949
Creator: Costello, George R.
System: The UNT Digital Library
Investigation of Separation of the Turbulent Boundary Layer (open access)

Investigation of Separation of the Turbulent Boundary Layer

"An investigation was conducted on a turbulent boundary layer near a smooth surface with pressure gradients sufficient to cause flow separation. The Reynolds number was high, but the speeds were entirely within the incompressible flow range. The investigation consisted of measurements of mean flow, three components of turbulence intensity, turbulent shearing stress, and correlations between two fluctuation components at a point and between the same component of different points" (p. 1).
Date: June 1, 1949
Creator: Schubauer, G. B. & Klebanoff, P. S.
System: The UNT Digital Library
Frequency Response of Linear Systems From Transient Data (open access)

Frequency Response of Linear Systems From Transient Data

"Methods are presented that use general correlative time-response input and output data for a linear system to determine the frequency-response function of that system. These methods give an exact description of any linear system for which such transient data are available. Examples are shown of application of a method to both an underdamped and a critically damped exact second-order system, and to an exact first-order system with and without dead time. Experimental data for a turbine-propeller engine showing the response of engine speed to change in propeller-blade angle are presented and analyzed" (p. 547).
Date: April 1, 1949
Creator: LaVerne, Melvin E. & Boksenbom, Aaron S.
System: The UNT Digital Library
Application of Radial-Equilibrium Condition to Axial-Flow Compressor and Turbine Design (open access)

Application of Radial-Equilibrium Condition to Axial-Flow Compressor and Turbine Design

"Basic general equations governing the three-dimensional compressible flow of gas through a compressor or turbine are given in terms of total enthalpy, entropy, and velocity components of the gas. Two methods of solution are obtained for the simplified, steady axially symmetric flow; one involves the use of a number of successive planes normal to the axis of the machine and short distances apart, and the other involves only three stations for a stage in which an appropriate radial-flow path is used. Methods of calculation for the limiting cases of zero and infinite blade aspect ratios and an approximate method of calculation for finite blade aspect ratio are also given" (p. 1).
Date: January 1, 1949
Creator: Wu, Chung-Hua & Wolfenstein, Lincoln
System: The UNT Digital Library
Equations for the Design of Two-Dimensional Supersonic Nozzles (open access)

Equations for the Design of Two-Dimensional Supersonic Nozzles

"Equations are presented for obtaining the wall coordinates of two-dimensional supersonic nozzles. The equations are based on the application of the method of characteristics to irrotational flow of perfect gases in channels. Curves and tables are included for obtaining the parameters required by the equations for the wall coordinates. A brief discussion of characteristics as applied to nozzle design is given to assist in understanding and using the nozzle-design method of this report. A sample design is shown" (p. 1).
Date: June 1, 1948
Creator: Pinkel, I. Irving
System: The UNT Digital Library
Velocity distributions on two-dimensional wing-duct inlets by conformal mapping (open access)

Velocity distributions on two-dimensional wing-duct inlets by conformal mapping

The conformal-mapping method of the Cartesian mapping function is applied to the determination of the velocity distribution on arbitrary two-dimensional duct-inlet shapes such as are used in wing installations. An idealized form of the actual wing-duct inlet is analyzed. The effects of leading edge stagger, inlet-velocity ratio, and section lift coefficients on the velocity distribution are included in the analysis. Numerical examples are given and, in part, compared with experimental data.
Date: April 1, 1947
Creator: Perl, W. & Moses, H. E.
System: The UNT Digital Library
An Analysis of the Full-Floating Journal Bearing (open access)

An Analysis of the Full-Floating Journal Bearing

Report discussing an analysis of the operating characteristics of a full-floating journal bearing, a bearing in which a floating sleeve is located between the journal and bearing surfaces, is presented together with charts from which the performance of such bearings may be predicted.
Date: January 1, 1947
Creator: Shaw, M. C. & Nussdorfer, T. J., Jr.
System: The UNT Digital Library
Cylinder-Temperature Correlation of a Single-Cylinder Liquid-Cooled Engine (open access)

Cylinder-Temperature Correlation of a Single-Cylinder Liquid-Cooled Engine

"An analysis based on nonboiling forced-convection heat-transfer theory is made of the cooling processes in liquid-cooled engine cylinders. Semiempirical equations that relate the average head and barrel temperatures with the primary engine and coolant parameters are derived. A correlation method based on these equations is applied to data obtained from previously reported investigations, which were conducted over large ranges of engine and coolant conditions with two liquid-cooled cylinders using water and various aqueous ethylene glycol solutions as coolants" (p. 285)
Date: October 1, 1946
Creator: Pinkel, Benjamin; Manganiello, Eugene J. & Bernardo, Everett
System: The UNT Digital Library
A Thermodynamic Study of the Turbojet Engine (open access)

A Thermodynamic Study of the Turbojet Engine

"Charts are presented for computing thrust, fuel consumption, and other performance values of a turbojet engine for any given set of operating conditions and component efficiencies. The effects of pressure losses in the inlet duct and the combustion chamber, of variation in physical properties of the gas as it passes through the system, of reheating of the gas due to turbine losses, and of change in mass flow by the addition of fuel are included. The principle performance chart shows the effects of primary variables and correction charts provide the effects of secondary variables and of turbine-loss reheat on the performance of the system" (p. 599).
Date: June 1, 1946
Creator: Pinkel, Benjamin & Karp, Irving M.
System: The UNT Digital Library
Quantitative Treatment of the Creep of Metals by Dislocation and Rate-Process Theories (open access)

Quantitative Treatment of the Creep of Metals by Dislocation and Rate-Process Theories

"An equation for the steady-state rate of creep has been derived by applying the theory of dislocations to the creep of pure metals. The form of this equation is in agreement with empirical equations describing creep rates. The theory was also used to predict the dependence of steady-state rate of creep on physical constants of the material and good agreement was obtained with data in the literature for pure annealed metals" (p. 169).
Date: January 1, 1946
Creator: Nowick, A. S. & Machlin, E. S.
System: The UNT Digital Library
Some Effects of Compressibility on the Flow Through Fans and Turbines (open access)

Some Effects of Compressibility on the Flow Through Fans and Turbines

"The laws of conservation of mass, momentum, and energy are applied to the compressible flow through a two-dimensional cascade of airfoils. A fundamental relation between the ultimate upstream and downstream flow angles, the inlet Mach number, and the pressure ratio across the cascade is derived. Comparison with the corresponding relation for incompressible flow shows large differences. The fundamental relation reveals two ranges of flow angles and inlet Mach numbers, for which no ideal pressure ratio exists" (p. 123).
Date: August 1, 1945
Creator: Perl, W. & Epstein, H. T.
System: The UNT Digital Library