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Determination of general relations for the behavior of turbulent boundary layers

Determination of general relations for the behavior of turbulent boundary layers

Date: January 1, 1943
Creator: Von Doenhoff, Albert E & Tetervin, Neal
Description: An analysis has been made of a considerable amount of data for turbulent boundary layers along wings and bodies of various shapes in order to determine the fundamental variables that control the development of turbulent boundary layers. It was found that the type of velocity distribution in the boundary layer could be expressed in terms of a single parameter. This parameter was chosen as the ratio of the displacement thickness to the momentum thickness of the boundary layer. The variables that control the development of the turbulent boundary layer apparently are: (1) the ratio of the nondimensional pressure gradient, expressed in terms of the local dynamic pressure outside the boundary layer and boundary-layer thickness, to the local skin-friction coefficient and (2) the shape of the boundary layer. An empirical equation has been developed in terms of these variables that, when used with the momentum equation and the skin-friction relation, makes it possible to trace the development of the turbulent boundary layer to the separation point.
Contributing Partner: UNT Libraries Government Documents Department
Discriminator for Photographic Analyzer

Discriminator for Photographic Analyzer

Date: 1943
Creator: Sands, M.
Description: Technical drawing of frequency discriminators and image analysis for nuclear reactors.
Contributing Partner: UNT Libraries Government Documents Department
Drag Measurements of a Protruding.50-Caliber Machine Gun with Barrel Jacket Removed

Drag Measurements of a Protruding.50-Caliber Machine Gun with Barrel Jacket Removed

Date: January 1, 1943
Creator: Luoma, Arvo A.
Description: Tests were made in 8-ft high-speed wind tunnel to determine the drag reduction possible by eliminating the barrel jacket of a protruding 50-caliber aircraft gun. It was found that the drag of a standard aircraft gun protruding into the air stream at right angles to the flow can be reduced by 23% by discarding the barrel jacket. At 300 mph and sea-level conditions, this amounts to a decrease in drag of from 83 to 64 pounds. A rough surface finish on the barrel was found to have no adverse effects on the drag of the barrel, the drag being actually less at high Mach Numbers.
Contributing Partner: UNT Libraries Government Documents Department
The Effect of Compressibility on the Growth of the Laminar Boundary Layer on Low-Drag Wings and Bodies

The Effect of Compressibility on the Growth of the Laminar Boundary Layer on Low-Drag Wings and Bodies

Date: January 1, 1943
Creator: Allen, H. Julian & Nitzberg, Gerald E.
Description: The development of the laminar boundary layer in a compressible fluid is considered. Formulas are given for determining the boundary-layer thickness and the ratio of the boundary-layer Reynolds number to the body Reynolds number for airfoils and bodies of revolution. It i s shown that the effect of compressibility will profoundly alter the Reynolds number corresponding to the upper limit of the range of the low-drag coefficients . The available data indicate that for low-drag and high critical compressibility speed airfoils and bodies of revolution, this effect is favorable.
Contributing Partner: UNT Libraries Government Documents Department
The effect of compressibility on two-dimensional tunnel-wall interference for a symmetrical airfoil

The effect of compressibility on two-dimensional tunnel-wall interference for a symmetrical airfoil

Date: January 1, 1943
Creator: Nitzberg, Gerald E
Description: Summary: The effective change in the velocity of flow past a wing section, caused by the presence of wind-tunnel walls, is known for potential flow. This theory is extended by investigation of the two-dimensional compressible flow past a thin Rankine Oval. It is shown that for a symmetrical section at zero angle of attack the velocity increment due to the tunnel walls in the incompressible case must be multiplied by the factor 1/1-M^2 to take account of compressibility effects. The Mach number, M, corresponds to conditions in the wind-tunnel test section with the model removed (p. 1.).
Contributing Partner: UNT Libraries Government Documents Department
Effect of fillers and of mixing procedure on the strength of plastic materials

Effect of fillers and of mixing procedure on the strength of plastic materials

Date: January 1, 1943
Creator: Kynoch, William & Patronsky, L A
Description: None
Contributing Partner: UNT Libraries Government Documents Department
The effect of mass distribution on the lateral stability and control characteristics of an airplane as determined by tests of a model in the free-flight tunnel

The effect of mass distribution on the lateral stability and control characteristics of an airplane as determined by tests of a model in the free-flight tunnel

Date: January 1, 1943
Creator: Campbell, John P & Seacord, Charles L , Jr
Description: The effects of mass distribution on lateral stability and control characteristics of an airplane have been determined by flight tests of a model in the NACA free-flight tunnel. In the investigation, the rolling and yawing moments of inertia were increased from normal values to values up to five times normal. For each moment-of-inertia condition, combinations of dihedral and vertical-tail area representing a variety of airplane configurations were tested. The results of the flight tests of the model were correlated with calculated stability and control characteristics and, in general, good agreement was obtained.
Contributing Partner: UNT Libraries Government Documents Department
Effect of Normal Pressure on the Critical Shear Stress of Curved Sheet

Effect of Normal Pressure on the Critical Shear Stress of Curved Sheet

Date: January 1, 1943
Creator: Rafel, Norman
Description: In order to determine the critical stresses caused by an outward acting pressure on the upper surface of a wing due to the difference in internal and external pressures, torsional tests were made on two curved-sheet specimens subjected to an outward acting normal pressure. Results show that an outward acting normal pressure appreciable raises the critical shear stress for an unstiffened curved sheet; the absolute increase in critical shear stress is slightly greater for a 30 in. rib spacing than for a 10 in. rib spacing.
Contributing Partner: UNT Libraries Government Documents Department
Effect of Rivet Holes on the Ultimate Strength Developed by 24S-T and Alclad 75S-T Sheet in Incomplete Diagonal Tension

Effect of Rivet Holes on the Ultimate Strength Developed by 24S-T and Alclad 75S-T Sheet in Incomplete Diagonal Tension

Date: January 1, 1943
Creator: Levin, L. Ross & Nelson, David H.
Description: Strength tests were made of a number of 24S-T and Alclad 75S-T aluminum-alloy shear webs to determine the effect of rivet or bolt holes on the shear strength. Data were obtained for webs which approached a condition of pure shear stress as well as for webs with well-developed diagonal tension. The rivet factor, (pitch minus diameter) divided by pitch, was varied from approximately 0.81 to 0.62. These tests indicated that the shear stresses on the gross section were nearly constant for all values of the rivet factor investigated if the other properties of the web were not changed.
Contributing Partner: UNT Libraries Government Documents Department
The effect on stability and control of a pusher propeller behind conventional tail surfaces as determined by tests of a powered model in the free-flight tunnel

The effect on stability and control of a pusher propeller behind conventional tail surfaces as determined by tests of a powered model in the free-flight tunnel

Date: January 1, 1943
Creator: Hollingworth, Thomas A
Description: None
Contributing Partner: UNT Libraries Government Documents Department
The exact solution of shear-lag problems in flat panels and box beams assumed rigid in the transverse direction

The exact solution of shear-lag problems in flat panels and box beams assumed rigid in the transverse direction

Date: January 1, 1943
Creator: Hildebrand, Francis B
Description: A mathematical procedure is herein developed for obtaining exact solutions of shear-lag problems in flat panels and box beams: the method is based on the assumption that the amount of stretching of the sheets in the direction perpendicular to the direction of essential normal stresses is negligible. Explicit solutions, including the treatment of cut-outs, are given for several cases and numerical results are presented in graphic and tabular form. The general theory is presented in a from which further solutions can be readily obtained. The extension of the theory to cover certain cases of non-uniform cross section is indicated. Although the solutions are obtained in terms of infinite series, the present developments differ from those previously given in that, in practical cases, the series usually converge so rapidly that sufficient accuracy is afforded by a small number of terms. Comparisons are made in several cases between the present results and the corresponding solutions obtained by approximate procedures devised by Reissner and by Kuhn and Chiarito.
Contributing Partner: UNT Libraries Government Documents Department
Exhaust-stack nozzle area and shape for individual cylinder exhaust-gas jet-propulsion system

Exhaust-stack nozzle area and shape for individual cylinder exhaust-gas jet-propulsion system

Date: January 1, 1943
Creator: Pinkel, Benjamin; Turner, Richard; Voss, Fred & Humble, Leroy V
Description: This report presents the results of an investigation conducted on the effect of exhaust-stack nozzle area, shape, and length on engine power, jet thrust, and gain in net thrust (engine propeller plus jet). Single-cylinder engine data were obtained using three straight stacks 25, 44, and 108 inches in length; an S-shaped stack, a 90 degree bend, a 180 degree bend, and a short straight stack having a closed branch faired into it. Each stack was fitted with nozzles varying in exit area from 0.91 square inch to the unrestricted area of the stack of 4.20 square inches. The engine was generally operated over a range of engine speeds from 1300 to 2100 r.p.m, inlet-manifold pressures from 22 to 30 inches of mercury absolute, and a fuel-air ratio of 0.08. The loss in engine power, the jet thrust, and the gain in net thrust are correlated in terms of several simple parameters. An example is given for determining the optimum nozzle area and the overall net thrust.
Contributing Partner: UNT Libraries Government Documents Department
Experimental Investigation of Impact in Landing on Water

Experimental Investigation of Impact in Landing on Water

Date: January 1, 1943
Creator: Kreps, R. L.
Description: The extent of agreement of the theoretical impact computations with the actual phenomenon has not as yet been fully clarified. There is on the one hand a certain imperfection in the theory (simplifying assumptions made) and on the other an insufficiency in the experimental data available. The object of our present paper is to show how far test results agree with the available approximate computation methods, to investigate in greater detail the physical nature of impact on water, and to perfect the experimental method of studying the phenomenon.
Contributing Partner: UNT Libraries Government Documents Department
An experimental survey of flow across banks of elliptical and pointed tubes

An experimental survey of flow across banks of elliptical and pointed tubes

Date: January 1, 1943
Creator: Palmer, Carl B
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane I : high-inlet-velocity cowling with propeller cuffs tested in high-speed level flight

Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane I : high-inlet-velocity cowling with propeller cuffs tested in high-speed level flight

Date: January 1, 1943
Creator: Johnston, J Ford
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane II : low-inlet-velocity cowling with axial-flow fan and propeller cuffs

Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane II : low-inlet-velocity cowling with axial-flow fan and propeller cuffs

Date: January 1, 1943
Creator: Voglewede, T J
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane III : low-inlet-velocity cowling without fan or propeller cuffs, with axial-flow fan alone, and with two different sets of propeller cuffs

Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane III : low-inlet-velocity cowling without fan or propeller cuffs, with axial-flow fan alone, and with two different sets of propeller cuffs

Date: January 1, 1943
Creator: Voglewede, T J
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane IV : high-inlet-velocity cowling tested in climb with and without propeller cuffs and in high-speed level flight without propeller cuffs

Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane IV : high-inlet-velocity cowling tested in climb with and without propeller cuffs and in high-speed level flight without propeller cuffs

Date: January 1, 1943
Creator: Voglewede, T J
Description: None
Contributing Partner: UNT Libraries Government Documents Department
The flow of a compressible fluid past a curved surface

The flow of a compressible fluid past a curved surface

Date: January 1, 1943
Creator: Kaplan, Carl
Description: An iteration method is employed to obtain the flow of a compressible fluid past a curved surface. The first approximation which leads to the Prandtl-Glauert rule, is based on the assumption that the flow differs but little from a pure translation. The iteration process then consists in improving this first approximation in order that it will apply to a flow differing from pure translatory motion to a greater degree. The method fails when the Mach number of the undisturbed stream reaches unity but permits a transition from subsonic to supersonic conditions without the appearance of a compression shock. The limiting value at which potential flow no longer exits is indicated by the apparent divergence of the power series representing the velocity of the fluid at the surface of the solid boundary.
Contributing Partner: UNT Libraries Government Documents Department
Full-scale tunnel tests of a flying model of the Curtiss XP-55 airplane

Full-scale tunnel tests of a flying model of the Curtiss XP-55 airplane

Date: January 1, 1943
Creator: Biebel, William J
Description: None
Contributing Partner: UNT Libraries Government Documents Department
General free to trim tests in NACA tank no.2 of three 1/8-full-size models of flying-boat hulls at low speeds-NACA models 116E-3K, 120R, and 143

General free to trim tests in NACA tank no.2 of three 1/8-full-size models of flying-boat hulls at low speeds-NACA models 116E-3K, 120R, and 143

Date: January 1, 1943
Creator: Carter, Arthur W
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Generalized selection charts for bombers powered by two, four, and six 3000-horsepower engines I : capacity and economy

Generalized selection charts for bombers powered by two, four, and six 3000-horsepower engines I : capacity and economy

Date: January 1, 1943
Creator: Hill, Paul R
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Hydrodynamic-stability tests of a model of a flying boat and of a planing surface having a small downward projection (hook) on the planing bottom near the step

Hydrodynamic-stability tests of a model of a flying boat and of a planing surface having a small downward projection (hook) on the planing bottom near the step

Date: January 1, 1943
Creator: Benson, James M
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Icing tests of aircraft-engine induction systems

Icing tests of aircraft-engine induction systems

Date: January 1, 1943
Creator: Kimball, Leo B
Description: None
Contributing Partner: UNT Libraries Government Documents Department